The magnetic field at the centre of a 50 cm long solenoid is 4 . 0 × 10 - 2 T when a current of 8 . 0 A flows through it. What is the number of turns in the solenoid? Take π = 3 . 14 .

Given: The length of solenoid, l = 50 cm = 0 . 5 m The magnetic field at the centre, B = 4 . 0 × 10 - 2 T Current in the solenoid, I = 8 . 0 A We know the magnetic field inside the solenoid is given as, B = μ 0 n I , Where n is number of turns per unit length. If N is the total number of turns, then n = N l ∴ B = μ 0 n I = μ 0 N l I ⇒ N = B l μ 0 I = 4 .0 × 10 − 2 × 0 .50 4 × 3 .14 × 10 − 7 × 8 = 1990

EASY

12th CBSE

IMPORTANT

Earn 100

A metallic wire is bent into the shape shown in Figure and carries a current $I$ . If $O$ is the common centre of all the three circular arcs of radii $r, 2 r$ and $3 r$ , find the magnetic field at the point $O$ .

Important Questions on Magnetic Effect of Current

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Problems for Practice>Q 1

A long solenoid consists of

20

turns per

cm

. What current is necessary to produce a magnetic field of

20 m T

inside the solenoid?

MEDIUM

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Problems for Practice>Q 2

A long solenoid is made by closely winding a wire of radius

0.5 mm

over a cylindrical non‐magnetic frame so that successive turns nearly touch each other. What will be the magnetic field at the centre of the solenoid if a current of

5 A

flows through it?

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Problems for Practice>Q 3

The magnetic field at the centre of a

50 cm

long solenoid is

4.0 \times 10^{- 2} T

when a current of

8.0 A

flows through it. What is the number of turns in the solenoid? Take

π = 3.14

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Problems for Practice>Q 4

A solenoid is

1.0 m

long and

3.0 cm

in diameter. It has five layers of windings of

850

turns each and carries a current of

5.0 A

. (i) What is

B

at its centre? (ii) What is the magnetic flux

ϕ_{B}

for a cross‐section of the solenoid at the centre?

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Problems for Practice>Q 5

A solenoid is

2.0 m

long and

3.0 cm

in diameter. It has

5

layers of winding of

1000

turns each and carries a current of

5.0 A

. What is the magnetic field at the centre? Use the standard value of

μ_{0}

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Problems for Practice>Q 6

A toroid has a core of inner radius

20 cm

and outer radius

22 cm

around which

4200

turns of a wire are wound. If the current in the wire is

10 A

, what is the magnetic field (i) inside the core of toroid (ii) outside the toroid and (iii) in the empty space surrounded by the toroid.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Problems for Practice>Q 7

A long straight solid conductor of radius

4 cm

carries a current of

2 A

, which is uniformly distributed over its circular cross‐section. Find the magnetic field at a distance of

3 cm

from the axis of the conductor.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 4 - Magnetic Effect of Current>Problems For Practice>Q 1

An electron moving with a velocity of

5.0 \times 10^{- 7} {ms}^{- 1}

enters a magnetic field of

1.0 W b m^{- 2}

at an angle of

30 °

. Calculate the force on the electron.

A metallic wire is bent into the shape shown in Figure and carries a current I. If O is the common centre of all the three circular arcs of radii r, 2r and 3r, find the magnetic field at the point O.

Important Questions on Magnetic Effect of Current

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A metallic wire is bent into the shape shown in Figure and carries a current $I$ . If $O$ is the common centre of all the three circular arcs of radii $r, 2 r$ and $3 r$ , find the magnetic field at the point $O$ .