Quiz — 149.._PDF serie onde 1 4 math+4 Sc 2020.pdf

Question 1 sur 10 20:00

[{"id":16649,"question":"Quelle est la relation entre la longueur d'onde λ, la fréquence f et la célérité v d'une onde ?","option_a":"λ = v × f","option_b":"λ = v \/ f","option_c":"λ = f \/ v","option_d":"λ = v + f","option_e":"","option_f":"","bonne_reponse":"b","explication":"La relation correcte est λ = v \/ f, où v est la célérité de l'onde, f sa fréquence et λ sa longueur d'onde.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"λ = v × f\", \"b\": \"λ = v \/ f\", \"c\": \"λ = f \/ v\", \"d\": \"λ = v ","_debug_options_count":4},{"id":16650,"question":"Une onde sonore se propage plus rapidement dans l'eau que dans l'air.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Vrai, car la célérité du son est plus élevée dans les milieux denses comme l'eau (environ 1500 m\/s) que dans l'air (340 m\/s).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":16651,"question":"Quelle équation différentielle décrit une onde progressive sinusoïdale ?","option_a":"∂²y\/∂t² = v² ∂²y\/∂x²","option_b":"∂y\/∂t = v ∂y\/∂x","option_c":"∂²y\/∂x² = v² ∂y\/∂t","option_d":"∂y\/∂x = v ∂y\/∂t","option_e":"","option_f":"","bonne_reponse":"a","explication":"L'équation d'onde progressive sinusoïdale est ∂²y\/∂t² = v² ∂²y\/∂x², où v est la célérité.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"∂²y\/∂t² = v² ∂²y\/∂x²\", \"b\": \"∂y\/∂t = v ∂y\/∂x","_debug_options_count":4},{"id":16652,"question":"La superposition de deux ondes de même fréquence et amplitude produit toujours une interférence constructive.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"b","explication":"Faux, cela dépend de la phase relative entre les deux ondes. Si elles sont en opposition de phase, l'interférence est destructive.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":16653,"question":"Quelle est la célérité de la lumière dans le vide (en m\/s) ?","option_a":"3 × 10^8","option_b":"3 × 10^5","option_c":"3 × 10^10","option_d":"3 × 10^6","option_e":"","option_f":"","bonne_reponse":"a","explication":"La célérité de la lumière dans le vide est d'environ 3 × 10^8 m\/s, une constante fondamentale en physique.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"3 × 10^8\", \"b\": \"3 × 10^5\", \"c\": \"3 × 10^10\", \"d\": \"3 × 10^6\"","_debug_options_count":4},{"id":16654,"question":"Un signal sinusoïdal a une fréquence de 50 Hz. Quelle est sa période T (en secondes) ?","option_a":"0,02 s","option_b":"0,2 s","option_c":"50 s","option_d":"20 s","option_e":"","option_f":"","bonne_reponse":"a","explication":"La période T est l'inverse de la fréquence : T = 1\/f = 1\/50 = 0,02 s.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"0,02 s\", \"b\": \"0,2 s\", \"c\": \"50 s\", \"d\": \"20 s\"}}","_debug_options_count":4},{"id":16655,"question":"Les ondes électromagnétiques peuvent se propager dans le vide.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Vrai, contrairement aux ondes mécaniques, les ondes électromagnétiques (comme la lumière) n'ont pas besoin d'un milieu matériel pour se propager.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":16656,"question":"Quelle est la formule de l'effet Doppler pour une source en mouvement ?","option_a":"f' = f × (v ± vs)\/v","option_b":"f' = f × v\/(v ± vs)","option_c":"f' = f × (v ± vl)\/v","option_d":"f' = f × v\/(v ± vl)","option_e":"","option_f":"","bonne_reponse":"b","explication":"La formule correcte est f' = f × v\/(v ± vs), où vs est la vitesse de la source et v la célérité de l'onde.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"f' = f × (v ± vs)\/v\", \"b\": \"f' = f × v\/(v ± vs)\", \"c\": \"f' = ","_debug_options_count":4},{"id":16657,"question":"Une onde stationnaire est le résultat de l'interférence de deux ondes progressives de même fréquence et amplitude.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Vrai, une onde stationnaire se forme lorsque deux ondes progressives de même fréquence et amplitude se superposent en opposition de phase.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":16658,"question":"Quelle est la longueur d'onde d'une onde électromagnétique de fréquence 60 MHz (en mètres) ?","option_a":"5 m","option_b":"0,5 m","option_c":"50 m","option_d":"500 m","option_e":"","option_f":"","bonne_reponse":"a","explication":"La longueur d'onde λ = v\/f = (3 × 10^8)\/(60 × 10^6) = 5 m.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"5 m\", \"b\": \"0,5 m\", \"c\": \"50 m\", \"d\": \"500 m\"}}","_debug_options_count":4}]