Tech Books Yard have 79 Magnetism for Free Download
Steel is hard to magnetize because of its
- A. Low permeability
- B. High permeability
- C. High density
- D. High retentivity
- Correct Answer: Option A
The magnetic flux through a wire loop in a magnetic field does not depend on
- A. The area of the loop
- B. The magnitude of the field
- C. The shape of the loop
- D. The angle between the plane of the loop and the direction
- Correct Answer: Option C
When a wire loop is rotated in a magnetic field the direction of the induced emf changes one in every _______ revolution
- A. 1/3
- B. 1/2
- C. 1/4
- D. 2/3
- Correct Answer: Option B
The induced emf in a wire loop that is moved parallel to a uniform magnetic field is
- A. Zero
- B. Dependent on the area of the loop
- C. Dependent on the shape of the loop
- D. Dependent on the magnitude of the field
- Correct Answer: Option A
The emf produced in a wire by its motion across a magnetic field does not depend upon the
- A. Diameter of the wire
- B. Length of the wire
- C. Orientation of the wire
- D. Flux density of the field
- Correct Answer: Option A
A current if flowing east along a power line. If the earth’s field is neglected, the direction of the magnetic field below it is
- A. North
- B. South
- C. East
- D. West
- Correct Answer: Option A
A permanent magnet does not exert a force on
- A. an unmagnetized iron bar
- B. a magnetized iron bar
- C. a moving electric charge
- D. a stationary electric charge
- Correct Answer: Option D
The magnetic field of a magnetized iron bar when strongly heated
- A. Becomes weaker
- B. Becomes stronger
- C. Reverses in direction
- D. is unchanged
- Correct Answer: Option A
The magnetic field of a bar magnet most closely resembles the magnetic field of
- A. a horseshoe magnet
- B. a straight current- carrying wire
- C. a stream of electrons moving parallel to one another
- D. a current- carrying wire loop
- Correct Answer: Option D
When the ferromagnetic substance is inserted in a current- carrying solenoid, the magnetic field is
- A. Greatly decreased
- B. Greatly increased
- C. Slightly decreased
- D. Slightly increased
- Correct Answer: Option B