47. The hot resistance of the bulb’s filament is higher than its cold resistance because the temperature co-efficient of the filament is
(a) zero
(b) negative
(c) positive
(d) about 2 ohms per degree
Ans: c
48. Heat in a conductor is produced on the passage of electric current due to
(a) reactance
(b) capacitance
(c) impedance
(d) resistance
Ans:
49. The insulation on a current carrying conductor is provided
(a) to prevent leakage of current
(b) to prevent shock
(c) both of above factors
(d) none of above factors
Ans: c
50. The thickness of insulation provided on the conductor depends on
(a) the magnitude of voltage on the conductor
(b) the magnitude of current flowing through it
(c) both (a) and (b)
(d) none of the above
Ans: a
51. Which of the following quantities remain the same in all parts of a series circuit ?
(a) Voltage
(b) Current
(c) Power
(d) Resistance
Ans: b
52. A 40 W bulb is connected in series with a room heater. If now 40 W bulb is replaced by 100 W bulb, the heater output will
(a) decrease
(b) increase
(c) remain same
(d) heater will burn out
Ans: b