Magnetism and Matter  MCQs

MCQs of Magnetism and Matter

Showing 21 to 30 out of 145 Questions
21.
A magnetic needle kept non-parallel to the magnetic field in a non-uniform magnetic field experiences
(a) a force but not a torque.
(b) a torque but not a force
(c) both a force and a torque.
(d) neither a force nor a torque
Answer:

Option (c)

22.
A steamer would like to move in the direction making an angle of 10° south with the west. The magnetic declination at that place is 17° west from the north. The steamer should move in a direction _____ .
(a) making an angle of 83° west with north pole of Earth.
(b) making an angle of 83° east with north pole of Earth.
(c) making an angle of 27° west with south pole of Earth.
(d) making an angle of 27° east with south pole of Earth.
Answer:

Option (a)

23.
A toroid wound with 100 turns/m of wire carries a current of 3 A. The core of toroid is made of iron having relative magnetic permeability of μr = 5000 under given conditions. The magnetic field inside the iron is _____ .(Take μ= 4π × 10-7 T m A-1)
(a) 0.15 T
(b) 0.47 T
(c) 1.5 × 10-2 T
(d) 1.88 T
Answer:

Option (d)

24.
The magnetism of a magnet is due to _____ .
(a) the Earth
(b) cosmic rays
(c) spin motion of electrons
(d) pressure of big magnet inside the Earth
Answer:

Option (c)

25.
A bar magnet is equivalent to a current-carrying _____ .
(a) toroid
(b) solenoid
(c) circular coil
(d) straight conductor
Answer:

Option (b)

26.
A magnetic wire is bent at its midpoint at an angle of 60°. If the length of the wire is l and its magnetic moment is m, then the magnetic moment of new shape of wire be _____ .
(a) 2m
(b) m
(c) m2
(d) m2
Answer:

Option (c)

27.
If a bar magnet of length 10 cm and pole strength 40 A m is placed at an angle of 30º in a uniform magnetic field of intensity 2 × 10-4T, then torque acting on it is _____ .
(a) 8× 10-4 Nm
(b) 6× 10-4 Nm
(c) 4× 10-4 Nm
(d) 2× 10-4 Nm
Answer:

Option (c)

28.
The horizontal component of Earth's magnetic field at any place is 0.36 × 10-4 Weber/m2. If the angle of dip of that place is 60º, then the value of vertical component of Earth's magnetic field will be _____ (in Wb/m2)
(a) 0.12 × 10-4
(b) 0.24 × 10-4
(c) 0.40 × 10-4
(d) 0.62 × 10-4
Answer:

Option (d)

29.
At a certain place, the horizontal component of the Earth's magnetic field is B0 and the angle of dip is 60º. The intensity of Earth's magnetic field at that place will be _____ .
(a) B0
(b) 2B0
(c) 2B0
(d) 3B0
Answer:

Option (b)

30.
A magnet makes 30 oscillations per minute at a place where horizontal component of Earth's magnetic field is 0.5 × 10-5 T. At another place, it takes 2.5 s to complete one oscillation. Value of horizontal component of Earth's magnetic field at that place is _____ .
(a) 0.24 × 10-6 T
(b) 0.32 × 10-6 T
(c) 0.48 × 10-6 T
(d) 0.72 × 10-6 T
Answer:

Option (b)

Showing 21 to 30 out of 145 Questions