electric current and magnetism - Category wise Question and Answer Practice Test with Solutions

Question : 6 [PCS (Pre) 2016]

An electric bulb is connected to 220 V generator. The current is 0.5A. The power of the bulb is

a) 440 W

b) 110 W

c) 110 V

d) 220 W

Question : 7 [IAS (Pre) 2000]

Fluorescent tubes are fitted with a choke. The choke coil

a) Reduces current in the circuit

b) Steps up the line voltage

c) Steps down the line voltage

d) Chokes low frequency current

Question : 8 [UPPCS (Pre) 2017]

A mobile phone charger is

a) A step up transformer

b) An inverter

c) A UPS

d) A step down transformer

Question : 9

Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to (E_g )_C , (E_g )_Si and (E_g )_Ge. Which of the following statements is true?

a) (E_g )_C < (E_g )_Ge < (E_g )_Si

b) (E_g )_C > (E_g )_Si > (E_g )_Ge

c) (E_g )_Si < (E_g )_Ge < (E_g )_C

d) (E_g )_C = (E_g )_Si = (E_g )_Ge

Question : 10

An oscillator is nothing but an amplifer with

a) negative feedback

b) large gain

c) positive feedback

d) no feedback