1. When electric current passes through a metallic conductor, its temperature rises. This is due to ?

collisions between conduction electrons and atoms

the release of conduction electrons from parent atoms

mutual collisions between metal atoms

mutual collisions between conducting electrons

Answer: collisions between conduction electrons and atoms

Explanation:


2. Whether circuit may be AC. or D.C. one, following is most effective in reducing the magnitude of the current ?

Reactor

Capacitor

Inductor

Resistor

Answer: Resistor

Explanation:


3. The minimum charge on an ion is ?

equal to the atomic number of the atom

equal to the charge of an electron

equal to the charge of the number of electrons in an atom

zero

Answer: equal to the charge of an electron

Explanation:


4. A field of force can exist only between ?

two molecules

two ions

two atoms

two metal particles

Answer: two ions

Explanation:


5. A substance whose molecules consist dissimilar atoms is called ?

semi-conductor

super-conductor

compound

insulator

Answer: compound

Explanation:


6. An electric filament bulb can be worked from ?

D.C. supply only

A.C. supply only

Battery supply only

All above

Answer: All above

Explanation:


7. An open resistor, when checked with an ohm-meter reads ?

zero

infinite

high but within tolerance

low but not zero

Answer: infinite

Explanation:


8. When resistance element of a heater fuses and then we reconnect it after removing a portion of it, the power of the heater will ?

decrease

increase

remain constant

none of the above

Answer: increase

Explanation:


9. Heat in a conductor is produced on the passage of electric current due to ?

reactance

capacitance

impedance

resistance

Answer: resistance

Explanation:


10. Resistance of a material always decreases if ?

temperature of material is decreased

temperature of material is increased

number of free electrons available become more

none of the above is correct

Answer: number of free electrons available become more

Explanation: