EASY
12th CBSE
IMPORTANT
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Explain how electron mobility changes for a good conductor when the applied potential difference is doubled at constant temperature.

Important Questions on Current Electricity

EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>HOTS Problems on Higher Order Thinking Skills>Q 11
Two wires X, Y have the same resistivity, but their cross-sectional areas are in the ratio 2:3 and lengths in the ratio 1:2. They are first connected in series and then in parallel to a d.c. source. Find out the ratio of the drift speeds of the electrons in the two wires for the two cases.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>HOTS Problems on Higher Order Thinking Skills>Q 12
The current through a wire depends on time as I=I0+αt, where I0=10 A and α=4 A s−1. Find the charge that flows across a section of the wire in 10 seconds.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>HOTS Problems on Higher Order Thinking Skills>Q 13
A uniform wire is cut into 10 segments increasing in length in equal steps, the resistance of the shortest segment is R and the resistances of the other segments increase in steps of 8 Ω. If the resistance of the longest segment is 2 R, find the value of R and hence find the resistance of the original wire.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>HOTS Problems on Higher Order Thinking Skills>Q 14
The resistivity of the material of a conductor of uniform cross-section varies along its length as ρ=ρ0(1+αx). Deduce the expression for the resistance of the conductor, if its length is L and area of cross-section is A.
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12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>HOTS Problems on Higher Order Thinking Skills>Q 15
One metre long metallic wire is broken into two unequal parts P and Q. The part P is uniformly extended into another wire R. The length of R is twice the length of P and the resistance of R is equal to that of Q. Find the ratio of the resistances of P and R and also the ratio of the lengths P and Q.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>HOTS Problems on Higher Order Thinking Skills>Q 16
A carbon filament has a resistance of 100 Ω at 0°C. What must be the resistance of a copper filament placed in series with carbon so that the combination has the same resistance at all temperatures? Temperature coefficient of resistance of carbon=−0.0007∘C−1 and that of copper is 0.004°C−1.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>HOTS Problems on Higher Order Thinking Skills>Q 17
Calculate the temperature at which the resistance of a conductor becomes 20% more than that its resistance at 27°C. The value of the temperature coefficient of resistance of the conductor is 2.0×10−4/K.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>HOTS Problems on Higher Order Thinking Skills>Q 18
The current through a conductor is 1 ampere when the temperature is 0° C and 0.7 ampere when the temperature is 100° C. What would be current when the temperature of the conductor is 1200° C?