Magnetic Effect of Current

What direction does the magnetic field show when the thumb is in the direction of the current and normal to the palm?

Opposite to the direction of the current
Direction of the thumb
Direction of the current
Perpendicular to the palm (correct)

What symbol represents a magnetic field directed perpendicular and out of the plane of the paper?

× (cross)
∙ (dot) (correct)
⋅ (circle)
→ (arrow)

What is the unit of permeability of air in CGS?

tesla/ampere
gauss/ampere
poise/ampere
dyne/ampere (correct)

If a coil of radius r has N turns, what is the magnetic field on its axis at a distance x from its centre?

Baxis = μ0 2πNi/4π(x + r²)³/² (D) Signup and view all the answers

How does the magnetic field at the centre of a coil vary with the number of turns, if the current and radius are constant?

Bcentre ∝ N (C) Signup and view all the answers

What is the direction of the magnetic field when the direction of current is reversed?

It is changed (B) Signup and view all the answers

What is a current element in Biot-Savart's Law?

The product of current and length of infinitesimally small segment of current carrying wire (A) Signup and view all the answers

What is the unit of permeability of air in S.I. system?

Henry/meter (B), Henry/meter (D) Signup and view all the answers

What is the expression for the magnetic field at a point 'P' due to a current element i dl?

dB = μ0 i dl sin θ / 4π r^2 (A) Signup and view all the answers

What is produced by a moving charge?

Both electric and magnetic fields (A) Signup and view all the answers

What is the direction of the magnetic field created by a current element?

Perpendicular to both the length element dl and the unit vector r̂ (B) Signup and view all the answers

What is the formula for calculating the magnetic field dB using the Biot-Savart Law?

dB = μ₀ × I × dl × r̂ / (4π r²) (A) Signup and view all the answers

What is the permeability of air in the Biot-Savart Law?

μ₀ (B) Signup and view all the answers

What is the direction of the magnetic lines of force according to Maxwell's cork screw rule?

Direction of rotation of the thumb (B) Signup and view all the answers

What is the rule used to determine the direction of magnetic field for a current-carrying circular conductor?

Right hand thumb rule of circular currents (D) Signup and view all the answers

What is the ratio of magnetic field at the centre of the coil and on its axis when x = ±a?

2 (B) Signup and view all the answers

What is the expression for the magnetic field at the centre of the coil when the number of turns and current are constant?

B ∝ 1/r (A) Signup and view all the answers

What is the magnetic field on the axis of the coil at a very large distance from the centre?

μ₀ Ni / 2πr² (B) Signup and view all the answers

What is the condition for the magnetic field at the centre of the coil to be equal to the magnetic field on its axis?

x = ±r (n²/3 - 1) (C) Signup and view all the answers

What is the expression for the magnetic field at the centre of the coil when x = ±5a/3?

Bc = 5/3 Ba (B) Signup and view all the answers

What is the direction of the magnetic field created by a current element with respect to the unit vector r̂?

Perpendicular to r̂ (A) Signup and view all the answers

What is the direction of the magnetic field at the centre of a coil with N turns, if the current and radius are constant?

Proportional to the number of turns (A) Signup and view all the answers

A current element is placed in a region of uniform magnetic field. What is the direction of the force experienced by the current element?

Perpendicular to both the magnetic field and the current element (C) Signup and view all the answers

A coil of radius r has N turns, and a current I flows through it. What is the direction of the magnetic field on its axis at a distance x from its centre?

Along the axis of the coil (C) Signup and view all the answers

What is the physical quantity that is proportional to the product of the current and the length of the current element in the Biot-Savart Law?

Magnetic field (D) Signup and view all the answers

What is the direction of the magnetic field at the centre of a coil if the current and radius are constant?

It is proportional to the number of turns. (D) Signup and view all the answers

What is the magnetic field on the axis of a coil at a distance x from its centre?

It is proportional to $mu_0 Ni / (x^2 + r^2)^{3/2}$ (C) Signup and view all the answers

If the current in a coil is reversed, what happens to the direction of the magnetic field?

It is reversed. (B) Signup and view all the answers

What is the expression for the magnetic field at the centre of a coil?

B = $mu_0 Ni / 4 extbackslash pi r^2$ (A) Signup and view all the answers

What is the direction of the magnetic field if the thumb is in the direction of the current and normal to the palm?

It is perpendicular to the direction of the current. (C) Signup and view all the answers