23. Which of the following statement is true both for a series and a parallel D.C. circuit?
(a) Elements have individual currents
(b) Currents are additive
(c) Voltages are additive
(d) Power are additive
Ans: d
24. Which of the following materials has a negative temperature co-efficient of resistance?
(a) Copper
(b) Aluminum
(c) Carbon
(d) Brass
Ans: c
25. Ohm’s law is not applicable to
(a) vacuum tubes
(b) carbon resistors
(c) high voltage circuits
(d) circuits with low current densities
Ans: a
26. Which is the best conductor of electricity ?
(a) Iron
(b) Silver
(c) Copper
(d) Carbon
Ans: b
27. For which of the following ‘ampere second’ could be the unit ?
(a) Reluctance
(b) Charge
(c) Power
(d) Energy
Ans: b
28. All of the following are equivalent to watt except
(a) (amperes) ohm
(b) joules/sec.
(c) amperes x volts
(d) amperes/volt
Ans: d