IIT JEE : Electromagnetic Induction Electromagnetic Waves QUESTIONS AND ANSWERS :: part3 : 21 to 25

Following IIT JEE Entrance Multiple choice objective type questions and answers will help you in Maths, Physics and Chemistry 2024 examinations :

21.A transformer is used to light a 100W and 110 V lamp from a 230 V mains. If the main current is 0.5 A, the efficiency of the transformer is

20%

50%

87%

67%

22.When power is drawn from the secondary coil of the transformer, the dynamic resistance

remains same

decreases

increases

fluctuates.

23.A 20V ac is applied to a circuit consisting of a resistance and a coil with negligible resistance. If the voltage across the resistance is 12 V, the voltage across the coil is

16 V

10 V

8 V

6 V

24.An A.C. voltmeter reads 20 V across a resistor, 30 V across an inductor and 15 V across a capacitor in LCR series circuit. In this case the supply voltage will be

100 V

60 V

50 V

25 V

25.The S.I. unit of magnitude flux is

Maxwell

Tesla

Weber

Henry

More Electromagnetic Induction Electromagnetic Waves QUESTIONS AND ANSWERS available in next pages