1. When we install a 2000 watt heater in the wire of the house, then the heater turns red when the wiring wires stay cool because?
(A) Heater element has more current than wiring
(B) Element wire is naked so can feel its heat
(C) Element registration is less than warping
(D) Element registration is higher than wiring
Answer- (D)
2. When we install a 1500 watt heater in the wiring of the house, the light of the bulb decreases because?
(A) More current is taken by the heater and less current is left for the bulb to burn.
(B) A high voltage is dropped parallel to the heater and the bulb receives a low voltage
(C) There is a high voltage drop in the line and the lamp and heater get low voltage.
(D) Due to over-voltage drop in the line, the bulb receives low voltage but no effect on the heater
Answer - (C)
3. Which effect is produced when electric current flows in the circuit?
(A) thermal effect occurs
(B) is the optical effect
(C) chemical effect
(D) All of the above are effects
Answer- (D)
4. What supplies are needed for transistor radios?
(A) low voltage DC
(B) low voltage AC
(C) High voltage AC
(D) High voltage DC
Answer- (A)
5. If 20 resistances of 20 ohms are connected in parallel, then what will be its combined resistance?
(A) 1
(B) 2
(C) 10
(D) 100
Answer- (A)
6. Which lamp has higher resistance?
(A) 200 watts, 250 volts
(B) 100 watts, 250 volts
(C) 60 watts, 250 volts
(D) 40 watts, 250 volts
Answer- (D)
7. Three low rated lamps have been added to the 250 volt supply in the series. Which lamp will give more light?
(A) 200 watts, 250 volts
(B) 100 watts, 250 volts
(C) 60 watts, 250 volts
(D) 40 watts, 250 volts
Answer- (A)
8. If a 100 watt 230 volt lamp is connected to a 250 volt supply?
(A) will give more light than 230 volt supply
(B) will give less light than 230 volt supply
(C) will give light as much as 230 volt supply
(D) None of these
Answer- (A)
9. When a heater coil burns, remove the burnt part and start the heater again, then the power of the heater?
(A) will decrease
(B) will increase
(C) as much as before
(D) All three of the above
Answer- (B)
10. When the electric current flows through the carbon filament, the resistance of the filament is reduced because?
(A) due to temperature rise
(B) due to increasing positive temperature
(C) Negative temperature due to coefficient
(D) due to decrease in insulating properties
Answer - (C)
11. Which of the following metals has the lowest resistivity?
(A) Copper
(B) Iron
(C) Iron
(D) Silver
Answer- (D)
12. The ability to conduct current of a copper wire whose diameter is twice that of other copper wire?
(A) will be double
(B) will be half
(C) will be four times
(D) will be three times
Answer - (C)
13. According to the second law of Kirchoffs?
(A) The mathematical sum of EMF is zero.
(B) the mathematical sum of the voltage drop is zero
(C) Mathematical sum of voltage drops and EMF's mathematical sum is zero
(D) Mathematical sum of voltage drops The mathematical sum of EMF is zero.
Answer- (D)
14. The resistance of each widening of a rotor connected in a delta is 3 ohms. Find the value of resistance between two pairs of terminals?
(A) 2 ohms
(B) 1.33 ohms
(C) 4 ohms
(D) 2 ohms
Answer- (D)
15. The voltage rating of 200 watt and 100 watt bulbs is the same, what will be the resistance of 100 watt bulbs?
(A) will be the same
(B) will be more
(C) will be less
(D) less first then later
Answer- (B)
16. D.C. In the case of
(A) The magnitude and direction of the stream remain constant
(B) The magnitude and direction of current changes over time
(C) the magnitude of the current changes over time
(D) the magnitude of the current remains constant
Answer :-( A)
17. When electric current passes through a bucket filled with water, a large amount of bubbling is seen. This shows what is the type of supply
(A) A.C.
(B) D.C.
(C) Either of the above
(D) None of the above
Ans: (B)
18. Resistance of carbon filament lamps when supply voltage increases.
(A) increases
(B) decreases
(C) remains same
(D) None of the above
Ans: (B)
19. Which of the following quantities remain the same in all parts of a series circuit?
(A) voltage
(B) present
(C) power
(D) resistance
Ans: (B)
20. A 40w bulb is connected in series with a room heater. If the 40w bulb is replaced with a 100w bulb now, the heater output will be
(A) lack
(B) growth
(C) stay the same
(D) the heater will burn
Ans: (B)
