Heating Effect of Current

Q. An electric bulb glows due to the _________ of electric current.

1. chemical effect
2. magnetic effect
3. heating effect
4. physical effect

Q. When current is passed through an electric bulb, its filament glows, but the wire leading current to the bulb does not glow because :

1. Less current flows in the leading wire as compared to that in the filament
2. The leading wire has more resistance than the filament
3. The leading wire has less resistance than the filament
4. Filament has coating of fluorescent material over it

Q.

If an electrical appliance of $R\Omega$ resistance draws a current ‘I’ for time ‘t’ and connected across a battery of potential V then the energy consumed by the appliance will be:

1. $\frac{V^2}{R}t$

2. All of the above

3. $VIt$

4. $I^{2}Rt$

Q.

In an hour glass the sand is replaced with electrons. The electrons flow down with a rate of electrons per sec, for a time duration of 1 hour. If in the middle section of the hour glass I place a resistor of 10 ohm. Find the heat energy dissipated by the bulb.

1. 1.6 × 10⁶ watt

2. 9.2 × 10⁶ watt

3. 4 × 10⁶ watt

4. 5.1× 10⁶ watt

Q.

In electric heating appliances the material of the heating element is

__

Q. Electric energy supplied to homes is measured by

1. voltmeter
2. ammeter
3. galvanometer
4. kilowatt-hour meter

Q. How can the rate of emission of electrons in a cathode ray tube be increased ?

1. By increasing the filament current
2. By decreasing the filament current
3. Can't be increased
4. None of the above

Q.

A current is passing through a resistor for a certain time. The current is doubled and the resistance halved while the time remains the same. What happens to the heating effect?

__

Q. A constant voltage is applied between the two ends of uniform metallic wire. Some heat is developed in it. If both length and radius of the wire are halved, then the heat developed in the same duration will become

1. one-fourth
2. half
3. same
4. twice

Q. Complete the following sentences:
A fuse wire is made of an alloy of ........... and............. If the current in a circuit rises too high, the fuse wire......

Q. What is the current through an electrical appliance of rating 5 kW, 200 V and can you use a fuse which is rated 8 A ?

1. 25 A, yes
2. 2.5 A, yes
3. 25 A, no
4. 2.5 A, no

Q. Mark the correct statement about the material to be used in fuse wire.

1. Low melting point
2. Low boiling point
3. High electric resistance
4. All