EASY
12th CBSE
IMPORTANT
Earn 100

A wire of certain radius is stretched so that its radius decreases by a factor n. Calculate its new resistance.

Important Questions on Current Electricity

EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 13
A wire 1 m long and 0.13 mm in diameter has a resistance of 4.2 Ω. Calculate the resistance of another wire of the same material whose length is 1.5 m and diameter 0.155 mm.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 14
A rheostat has 100 turns of a wire of radius 0.4 mm having resistivity 4.2×10−7Ωm. The diameter of each turn is 3 cm. What is the maximum value of resistance that it can introduce?
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 15
Given that resistivity of copper is 1.68×10−8Ωm. Calculate the amount of copper required to draw a wire 10 km long having resistance of 10 Ω. The density of copper is 8.9×103kg m-3
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 16
The size of a carbon block is 1.0 cm×1.0 cm×50 cm. Find its resistance (i) between the opposite square faces (ii) between the opposite rectangular faces of the block. The resistivity of carbon is 3.5×10−5Ω cm
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 17
Two wires A and B of the same material have their lengths in the ratio 1:5 and diameters in the ratio 3:2. If the resistance of the wire B is 180 Ω, find the resistance of the wire A.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 18
A uniform wire is cut into four segments. Each segment is twice as long as the earlier segment. If the shortest segment has a resistance of 4 Ω, find the resistance of the original wire.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 19
Calculate the conductance and conductivity of a wire of resistance 0.01 Ω, area of cross-section 10−4m2 and length 0.1 m.
EASY
12th CBSE
IMPORTANT
New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 1
The free electrons of a copper wire of cross-sectional area 10−6m2 acquire a drift velocity of 10−4m/s when a certain potential difference is applied across the wire. Find the current flowing in the wire if the density of free electrons in copper is 8.5×1028 electrons/m3.