COMPASSLearning

Talk to us Register Login

CBSE Class 12 · 2012 · All India · Magnetic Effects of CurrentLong Answer

(a) Explain, giving reasons, the basic difference in converting a galvanometer into (i) a voltmeter and (ii) an ammeter. (b) Two long straight parallel conductors carrying steady currents

I_{1}

and

I_{2}

are separated by a distance

d

. Explain briefly, with a suitable diagram, how the magnetic field due to one conductor acts on the other. Hence deduce the expression for the force between the two conductors and mention its nature.

Solution

(a) A \textbf{voltmeter} must draw negligible current, so a \textbf{high resistance} is added in series (

R = \frac{V}{I _{g}} - G

). An \textbf{ammeter} must pass large current with little disturbance, so a \textbf{low shunt} is added in parallel (

S = \frac{I _{g}}{I - I _{g}} G

). (b) Conductor 1's field at conductor 2 is

B_{1} = \frac{μ _{0} I _{1}}{2 π d}

, giving force per unit length

\frac{F}{ℓ} = B_{1} I_{2} = \frac{μ _{0} I _{1} I _{2}}{2 π d},

attractive when the currents are in the same direction and repulsive when opposite.

CBSE Class 12 Board · 2012 · All India · Subjective

Practise more: all CBSE board PYQs on Magnetic Effects of Current →

More board questions on Magnetic Effects of Current