Current Electricity  MCQs

MCQs of Current Electricity

Showing 111 to 119 out of 119 Questions
111.
n resistors of resistance r are connected to a battery of emf ε and internal resistance r. The ratio of terminal voltage to emf of battery = _____.
(a) n
(b) nn+1
(c) 1n+1
(d) n+1n
Answer:

Option (b)

112.
Equivalent resistance of n resistors having same resistance r when connected in parallel is R. Equivalent resistance When connected in series = _____.
(a) nR
(b) Rn
(c) Rn2
(d) n2R
Answer:

Option (d)

113.
Resistance of a long wire of uniform cross-section is R. It is cut into n equal pieces. Equivalent resistance of these pieces when connected parallel is R', then R' =_____.
(a) Rn
(b) nR
(c) Rn2
(d) R
Answer:

Option (c)

114.
A wire of radius r has resistance R. if it is converted into a wire of to radius r2, its resistance will be _____.
(a) 16R
(b) 2R
(c) 4R
(d) zero
Answer:

Option (a)

115.
Electric current is passed through a resistance R1 for time t form an electric cell. Now current is passed through a resistance R2 for the same time from the same cell. Internal resistance of the cell is _____, if the joule heat developed in both resistors is the same.
(a) R1+ R22
(b) R1- R22
(c) R1R2
(d) R1R2
Answer:

Option (d)

116.
Two resistors are connected (a) in series (b) in parallel. The equivalent resistance in two cases are 9 ohms and 2 ohms respectively. The resistors are _____.
(a) 2 Ω and 7 Ω
(b) 3 Ω and 6 Ω
(c) 3 Ω and 9 Ω
(d) 5 Ω and 4 Ω
Answer:

Option (b)

117.
Length of a heating filament is reduced by 20 %, then its power will _____.
(a) decrease by 20 %
(b) increase by 20 %
(c) increase by 25 %
(d) increase by 40 %
Answer:

Option (c)

118.
What maximum power can be obtained from a battery of emf ε and internal resistance r connected with an external resistance R ?
(a) ε24r
(b) ε23r
(c) ε22r
(d) ε2r
Answer:

Option (a)

119.
A wire of 20 Ω resistance is passed through ice and 220 V is supplied. What is the rate of melting of the ice ? latent heat of melting of ice = 80 cal/g.
(a) 6·56 g/s
(b) 7·2 g/s
(c) 1·92 g/s
(d) 0·85 g/s
Answer:

Option (b)

Showing 111 to 119 out of 119 Questions