A moving coil galvanometer of resistance G gives a full scale deflection for a current I g Use the suitable circuit diagram to convert it into an ammeter of range 0 to I I > I g . Deduce the expression for the shunt required for this conversion. Hence write the expression for the resistance of the ammeter thus obtained.

Given: The resistance of galvanometer, = G Current in galvanometer for full-scale deflection, I g The range of ammeter, 0 to I Let the required shunt resistance is S and the current through the shunt is I - I g The shunt resistance is connected in parallel with the galvanometer. Hence, P.D. across the galvanometer = P.D. across the shunt I g G = I - I g S ⇒ S = I g I - I g × G Now the total resistance of ammeter, R A = G S G + S < S

Write the expression for the magnetic force F → acting on a charged particle q moving with velocity v → in the presence of the magnetic field B → in a vector form.

Given, Magnetic force F → acting on a charged particle q with velocity v → in presence of magnetic field F → = q v → × B →

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12th CBSE

IMPORTANT

Earn 100

A moving coil galvanometer consists of a rectangular coil of $N$ turns, each of area $A$ , suspended in a radial magnetic field of flux density $B$ . Derive the expression for the torque on the coil, when current $I$ passes through it. Draw a suitable labelled diagram.

Important Questions on Magnetic Effect of Current

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12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Text Based Exercises>Q 30

A moving coil galvanometer of resistance

G

gives a full scale deflection for a current

I_{g}

Use the suitable circuit diagram to convert it into an ammeter of range

0

I (I > I_{g})

. Deduce the expression for the shunt required for this conversion. Hence write the expression for the resistance of the ammeter thus obtained.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Text Based Exercises>Q 31

Explain how will you convert a galvanometer into a voltmeter to read a maximum potential difference of

V

volts. Can one use a voltmeter to measure the emf of a cell? Justify your answer.

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12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Text Based Exercises>Q 32

Write the expression for the magnetic force

\vec{F}

acting on a charged particle

q

moving with velocity

\vec{v}

in the presence of the magnetic field

\vec{B}

in a vector form.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Text Based Exercises>Q 32

Show that no work is done and no change in the magnitude of the velocity of the particle is produced by this force.

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12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Text Based Exercises>Q 32

Hence define the unit of magnetic field.

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12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Text Based Exercises>Q 33

Three long straight parallel wires are kept as shown in Figure. The wire $(3)$ (3) carries a current $I$ . The direction of flow of current $I$ in wire $(3)$ , is such that the net force, on wire $(1)$ , due to the other two wires is zero.
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12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Text Based Exercises>Q 33

Three long straight parallel wires are kept as shown in Figure. The wire $(3)$ (3) carries a current $I$ . By reversing the direction of $I$ , the net force, on wire $(2)$ , due to the other two wires, becomes zero. What will be the directions of current $I$ , in the two cases? Also, obtain the relation between the magnitudes of currents $I_{1}, I_{2}$ and $I$ .
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12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Text Based Exercises>Q 34

Two long straight parallel conductors carrying steady currents

I_{a}

and

I_{b}

along the same direction are separated by a distance

d

. How does one explain the force of attraction between them ? If a third conductor carrying a current

I_{c}

in the opposite direction is placed just in the middle of these conductors, find the resultant force acting on the third conductor.

A moving coil galvanometer consists of a rectangular coil of N turns, each of area A, suspended in a radial magnetic field of flux density B. Derive the expression for the torque on the coil, when current I passes through it. Draw a suitable labelled diagram.

Important Questions on Magnetic Effect of Current

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A moving coil galvanometer consists of a rectangular coil of $N$ turns, each of area $A$ , suspended in a radial magnetic field of flux density $B$ . Derive the expression for the torque on the coil, when current $I$ passes through it. Draw a suitable labelled diagram.