Question

45. When the diameter of a wire is doubled, its resistance becomes A Double D. One-fourth B. Four times C. One-half 46. The rule which indicates the magnetic field in a current carrying straight conductor is A. Right hand thumb rule B. Fleming's Left-hand rule D. Screw rule C. Fleming's right-hand rule​

Answer 1

Answer:

Decreases four times

The resistance of a conductor of length L and diameter d is given by R=

π(d/2)

2

ρL

where ρ= resistivity of material of conductor.

When diameter is doubled, the resistance becomes R

′

=

π(2d/2)

2

ρL

=R/4