Ecrit par ✅ Quiz : Transformateurs
Ce quiz contient 20 questions.
Note : Placeholder pour valider la structure. Le JSON converti est conservé ci-dessous pour l’import final des vraies questions Tutor LMS.
JSON Tutor LMS-ready
{
"quiz_title": "Transformateurs",
"quiz_slug": "07_transformateurs_quiz",
"quiz_description": "Quiz Edu509 : Transformateurs",
"quiz_settings": {
"time_limit": {
"time_value": 0,
"time_type": "minutes"
},
"hide_quiz_time_display": false,
"attempts_allowed": 0,
"passing_grade": 70,
"max_questions_for_answer": 0,
"questions_order": "rand",
"hide_question_number_overview": false,
"short_answer_characters_limit": 200
},
"questions": [
{
"question_order": 1,
"question_title": "Un transformateur possède 300 spires au primaire et 1200 spires au secondaire. Si la tension efficace au primaire est de \\\\( 50\\\\ \\\\mathrm{V} \\\\), quelle est la tension efficace au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La loi de transformation donne \\\\( U_s = U_p \\\\times \\\\frac{N_s}{N_p} = 50 \\\\times \\\\frac{1200}{300} = 50 \\\\times 4 = 200\\\\ \\\\mathrm{V} \\\\).",
"answers": [
{
"answer_title": "200\\\\ \\\\mathrm{V}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "12,5\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "100\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "400\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 2,
"question_title": "Un transformateur idéal a \\\\( N_p = 800 \\\\) spires et \\\\( N_s = 200 \\\\) spires. Si le courant au secondaire est \\\\( 4,0\\\\ \\\\mathrm{A} \\\\), quel est le courant au primaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "Pour un transformateur idéal, \\\\( \\\\frac{I_s}{I_p} = \\\\frac{N_p}{N_s} \\\\). Donc \\\\( I_p = I_s \\\\times \\\\frac{N_s}{N_p} = 4,0 \\\\times \\\\frac{200}{800} = 4,0 \\\\times 0,25 = 1,0\\\\ \\\\mathrm{A} \\\\).",
"answers": [
{
"answer_title": "1,0\\\\ \\\\mathrm{A}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "16,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "0,5\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "2,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 3,
"question_title": "Un transformateur abaisseur a une tension primaire de \\\\( 230\\\\ \\\\mathrm{V} \\\\) et une tension secondaire de \\\\( 23\\\\ \\\\mathrm{V} \\\\). Si le primaire a 1150 spires, combien de spires y a-t-il au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La loi de transformation donne \\\\( \\\\frac{U_s}{U_p} = \\\\frac{N_s}{N_p} \\\\). Donc \\\\( N_s = N_p \\\\times \\\\frac{U_s}{U_p} = 1150 \\\\times \\\\frac{23}{230} = 1150 \\\\times 0,1 = 115 \\\\).",
"answers": [
{
"answer_title": "115",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "230",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "575",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "50",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 4,
"question_title": "Un transformateur idéal reçoit \\\\( 120\\\\ \\\\mathrm{V} \\\\) au primaire et fournit \\\\( 12\\\\ \\\\mathrm{V} \\\\) au secondaire. Si le courant au secondaire est \\\\( 5,0\\\\ \\\\mathrm{A} \\\\), quel est le courant au primaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La puissance est conservée : \\\\( U_p I_p = U_s I_s \\\\). Donc \\\\( I_p = \\\\frac{U_s I_s}{U_p} = \\\\frac{12 \\\\times 5,0}{120} = \\\\frac{60}{120} = 0,6\\\\ \\\\mathrm{A} \\\\).",
"answers": [
{
"answer_title": "0,5\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 1
},
{
"answer_title": "0,25\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "0,6\\\\ \\\\mathrm{A}",
"is_correct": true,
"answer_order": 3
},
{
"answer_title": "5,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 5,
"question_title": "Un transformateur réel a un rendement de \\\\( 90\\\\% \\\\). Si la puissance au primaire est \\\\( 200\\\\ \\\\mathrm{W} \\\\), quelle est la puissance utile délivrée au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "Le rendement est \\\\( \\\\eta = \\\\frac{P_s}{P_p} \\\\). Donc \\\\( P_s = \\\\eta \\\\times P_p = 0,90 \\\\times 200 = 180\\\\ \\\\mathrm{W} \\\\).",
"answers": [
{
"answer_title": "180\\\\ \\\\mathrm{W}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "220\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "20\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "90\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 6,
"question_title": "Un transformateur élévateur a \\\\( N_p = 400 \\\\), \\\\( N_s = 1600 \\\\), et \\\\( U_p = 30\\\\ \\\\mathrm{V} \\\\). Quelle est la tension au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La loi de transformation donne \\\\( U_s = U_p \\\\times \\\\frac{N_s}{N_p} = 30 \\\\times \\\\frac{1600}{400} = 30 \\\\times 4 = 120\\\\ \\\\mathrm{V} \\\\).",
"answers": [
{
"answer_title": "120\\\\ \\\\mathrm{V}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "7,5\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "60\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "240\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 7,
"question_title": "Un transformateur idéal a \\\\( U_p = 100\\\\ \\\\mathrm{V} \\\\), \\\\( I_p = 2,0\\\\ \\\\mathrm{A} \\\\), \\\\( N_p = 500 \\\\), \\\\( N_s = 100 \\\\). Quel est le courant au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La puissance est conservée : \\\\( U_p I_p = U_s I_s \\\\). \\\\( U_s = U_p \\\\times \\\\frac{N_s}{N_p} = 100 \\\\times \\\\frac{100}{500} = 20\\\\ \\\\mathrm{V} \\\\). Donc \\\\( I_s = \\\\frac{U_p I_p}{U_s} = \\\\frac{100 \\\\times 2,0}{20} = 10,0\\\\ \\\\mathrm{A} \\\\).",
"answers": [
{
"answer_title": "10,0\\\\ \\\\mathrm{A}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "0,4\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "2,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "0,2\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 8,
"question_title": "Un transformateur possède \\\\( N_p = 600 \\\\) spires et \\\\( N_s = 2400 \\\\) spires. Si la tension au primaire est \\\\( 100\\\\ \\\\mathrm{V} \\\\), quelle est la tension au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La loi de transformation donne \\\\( U_s = U_p \\\\times \\\\frac{N_s}{N_p} = 100 \\\\times \\\\frac{2400}{600} = 100 \\\\times 4 = 400\\\\ \\\\mathrm{V} \\\\).",
"answers": [
{
"answer_title": "400\\\\ \\\\mathrm{V}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "25\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "150\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "600\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 9,
"question_title": "Un transformateur réel a un rendement de \\\\( 95\\\\% \\\\). Si la puissance au primaire est \\\\( 300\\\\ \\\\mathrm{W} \\\\), quelle est la puissance utile au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "Le rendement est \\\\( \\\\eta = \\\\frac{P_s}{P_p} \\\\). Donc \\\\( P_s = 0,95 \\\\times 300 = 285\\\\ \\\\mathrm{W} \\\\).",
"answers": [
{
"answer_title": "285\\\\ \\\\mathrm{W}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "315\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "15\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "190\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 10,
"question_title": "Un transformateur idéal a \\\\( N_p = 1000 \\\\), \\\\( N_s = 250 \\\\), \\\\( U_p = 220\\\\ \\\\mathrm{V} \\\\). Quelle est la tension au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La loi de transformation donne \\\\( U_s = U_p \\\\times \\\\frac{N_s}{N_p} = 220 \\\\times \\\\frac{250}{1000} = 220 \\\\times 0,25 = 55\\\\ \\\\mathrm{V} \\\\).",
"answers": [
{
"answer_title": "55\\\\ \\\\mathrm{V}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "880\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "110\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "44\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 11,
"question_title": "Un transformateur élévateur a \\\\( N_p = 200 \\\\), \\\\( N_s = 1000 \\\\), \\\\( U_p = 24\\\\ \\\\mathrm{V} \\\\). Quelle est la tension au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La loi de transformation donne \\\\( U_s = U_p \\\\times \\\\frac{N_s}{N_p} = 24 \\\\times \\\\frac{1000}{200} = 24 \\\\times 5 = 120\\\\ \\\\mathrm{V} \\\\).",
"answers": [
{
"answer_title": "120\\\\ \\\\mathrm{V}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "48\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "12\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "240\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 12,
"question_title": "Un transformateur idéal a \\\\( U_p = 230\\\\ \\\\mathrm{V} \\\\), \\\\( N_p = 500 \\\\), \\\\( N_s = 100 \\\\), et le courant au secondaire est \\\\( 2,0\\\\ \\\\mathrm{A} \\\\). Quel est le courant au primaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La puissance est conservée : \\\\( U_p I_p = U_s I_s \\\\). \\\\( U_s = 230 \\\\times \\\\frac{100}{500} = 46\\\\ \\\\mathrm{V} \\\\). \\\\( I_p = \\\\frac{U_s I_s}{U_p} = \\\\frac{46 \\\\times 2,0}{230} = 0,40\\\\ \\\\mathrm{A} \\\\).",
"answers": [
{
"answer_title": "0,40\\\\ \\\\mathrm{A}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "2,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "1,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "4,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 13,
"question_title": "Un transformateur réel a un rendement de \\\\( 92\\\\% \\\\), \\\\( U_p = 120\\\\ \\\\mathrm{V} \\\\), \\\\( N_p = 300 \\\\), \\\\( N_s = 1200 \\\\), \\\\( I_p = 2,5\\\\ \\\\mathrm{A} \\\\). Quelle est la puissance utile au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "Puissance primaire : \\\\( P_p = 120 \\\\times 2,5 = 300\\\\ \\\\mathrm{W} \\\\). Puissance utile : \\\\( P_s = 0,92 \\\\times 300 = 276\\\\ \\\\mathrm{W} \\\\).",
"answers": [
{
"answer_title": "276\\\\ \\\\mathrm{W}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "300\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "120\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "240\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 14,
"question_title": "Un transformateur idéal a \\\\( N_p = 600 \\\\), \\\\( N_s = 150 \\\\), \\\\( U_p = 120\\\\ \\\\mathrm{V} \\\\), \\\\( I_s = 8,0\\\\ \\\\mathrm{A} \\\\). Quel est le courant au primaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La puissance est conservée : \\\\( U_p I_p = U_s I_s \\\\). \\\\( U_s = 120 \\\\times \\\\frac{150}{600} = 30\\\\ \\\\mathrm{V} \\\\). \\\\( I_p = \\\\frac{U_s I_s}{U_p} = \\\\frac{30 \\\\times 8,0}{120} = 2,0\\\\ \\\\mathrm{A} \\\\).",
"answers": [
{
"answer_title": "2,0\\\\ \\\\mathrm{A}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "8,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "4,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "1,5\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 15,
"question_title": "Un transformateur possède \\\\( N_p = 900 \\\\) spires et \\\\( N_s = 300 \\\\) spires. Si la tension au primaire est \\\\( 180\\\\ \\\\mathrm{V} \\\\), quelle est la tension au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La loi de transformation donne \\\\( U_s = U_p \\\\times \\\\frac{N_s}{N_p} = 180 \\\\times \\\\frac{300}{900} = 180 \\\\times 0,333 = 60\\\\ \\\\mathrm{V} \\\\).",
"answers": [
{
"answer_title": "60\\\\ \\\\mathrm{V}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "540\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "90\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "30\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 16,
"question_title": "Un transformateur idéal a \\\\( U_p = 220\\\\ \\\\mathrm{V} \\\\), \\\\( N_p = 1100 \\\\), \\\\( N_s = 220 \\\\), \\\\( P_s = 44\\\\ \\\\mathrm{W} \\\\). Quel est le courant au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La tension secondaire : \\\\( U_s = 220 \\\\times \\\\frac{220}{1100} = 44\\\\ \\\\mathrm{V} \\\\). \\\\( I_s = \\\\frac{P_s}{U_s} = \\\\frac{44}{44} = 1,0\\\\ \\\\mathrm{A} \\\\).",
"answers": [
{
"answer_title": "1,0\\\\ \\\\mathrm{A}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "0,2\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "2,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "0,4\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 17,
"question_title": "Un transformateur réel a un rendement de \\\\( 80\\\\% \\\\). Si la puissance au primaire est \\\\( 500\\\\ \\\\mathrm{W} \\\\), quelle est la puissance utile au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "Le rendement est \\\\( \\\\eta = \\\\frac{P_s}{P_p} \\\\). Donc \\\\( P_s = 0,80 \\\\times 500 = 400\\\\ \\\\mathrm{W} \\\\).",
"answers": [
{
"answer_title": "400\\\\ \\\\mathrm{W}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "500\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "100\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "600\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 18,
"question_title": "Un transformateur possède \\\\( N_p = 1200 \\\\) spires et \\\\( N_s = 300 \\\\) spires. Si la tension au primaire est \\\\( 240\\\\ \\\\mathrm{V} \\\\), quelle est la tension au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La loi de transformation donne \\\\( U_s = U_p \\\\times \\\\frac{N_s}{N_p} = 240 \\\\times \\\\frac{300}{1200} = 240 \\\\times 0,25 = 60\\\\ \\\\mathrm{V} \\\\).",
"answers": [
{
"answer_title": "60\\\\ \\\\mathrm{V}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "80\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "120\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "180\\\\ \\\\mathrm{V}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 19,
"question_title": "Un transformateur idéal a \\\\( U_p = 110\\\\ \\\\mathrm{V} \\\\), \\\\( N_p = 220 \\\\), \\\\( N_s = 1100 \\\\), \\\\( I_p = 0,5\\\\ \\\\mathrm{A} \\\\). Quel est le courant au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "La puissance est conservée : \\\\( U_p I_p = U_s I_s \\\\). \\\\( U_s = 110 \\\\times \\\\frac{1100}{220} = 110 \\\\times 5 = 550\\\\ \\\\mathrm{V} \\\\). \\\\( I_s = \\\\frac{U_p I_p}{U_s} = \\\\frac{110 \\\\times 0,5}{550} = \\\\frac{55}{550} = 0,1\\\\ \\\\mathrm{A} \\\\).",
"answers": [
{
"answer_title": "0,1\\\\ \\\\mathrm{A}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "2,5\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "0,5\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "1,0\\\\ \\\\mathrm{A}",
"is_correct": false,
"answer_order": 4
}
]
},
{
"question_order": 20,
"question_title": "Un transformateur réel a un rendement de \\\\( 85\\\\% \\\\). Si la puissance au primaire est \\\\( 400\\\\ \\\\mathrm{W} \\\\), quelle est la puissance utile au secondaire ?",
"question_type": "single_choice",
"question_mark": 1,
"answer_required": true,
"randomize_question": false,
"show_question_mark": true,
"question_description": "",
"question_explanation": "Le rendement est \\\\( \\\\eta = \\\\frac{P_s}{P_p} \\\\). Donc \\\\( P_s = 0,85 \\\\times 400 = 340\\\\ \\\\mathrm{W} \\\\).",
"answers": [
{
"answer_title": "340\\\\ \\\\mathrm{W}",
"is_correct": true,
"answer_order": 1
},
{
"answer_title": "360\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 2
},
{
"answer_title": "85\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 3
},
{
"answer_title": "400\\\\ \\\\mathrm{W}",
"is_correct": false,
"answer_order": 4
}
]
}
]
}