Basic Electrical Mcqs

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

A. decrease
B. increase
C. remain constant
D. none of the above

Copper wire of certain length and resistance is drawn out to three times its length without change in volume, the new resistance of wire becomes__________?

A. 1/9 times
B. 3 times
C. 9 times
D. unchanged

74. Sparking occurs when a load is switched off because the circuit has high_________?

A. resistance
B. inductance
C. capacitance
D. impedance

Switching of a lamp in house produces noise in the radio. This is because switching operation produces________?

A. arcs across separating contacts
B. mechanical noise of high intensity
C. both mechanical noise and arc between contacts
D. none of the above

For testing appliances, the wattage of test lamp should be_____________?

A. very low
B. low
C. high
D. any value

Bulbs in street lighting are all connected in_____________?

A. parallel
B. series
C. series-parallel
D. end-to-end

When electric current passes through a bucket full of water, lot of bubbling is observeD. This suggests that the type of supply is____________?

A. A. C.
B. D. C.
C. any of above two
D. none of the above

In the case of direct current____________?

A. magnitude and direction of current remains constant
B. magnitude and direction of current changes with time
C. magnitude of current changes with time
D. magnitude of current remains constant

Two lamps 100 W and 40 W are connected in series across 230 V (alternating). Which of the following statement is correct ?

A. 100 W lamp will glow brighter
B. 40 W lamp will glow brighter
C. Both lamps will glow equally bright
D. 40 W lamp will fuse

In a lamp load when more than one lamp are switched on the total resistance of the load_____________?

A. increases
B. decreases
C. remains same
D. none of the above