## Magnetism & Matter

Class 12 Physics Chapter 5 Objective in English : Here you can find class 12th physics Objective questions for board exam 2024. Magnetism & Matter objective questions is very important for board exam 2023 – 2024. mcq questions for class 12 physics chapter 5 in English. important question website

## 12th Physics Chapter 5 Objective Questions in English

1. The permeability (μ) of a ferromagnetic substance is : (B.S.E.B. , 2012)

(a) μ > 1

(b) μ = 0

(c) μ < 1

(d) μ = 0

1. Nickel is :

(a) Diamagnetic

(b) Paramagnetic

(c) Ferromagnetic

(d) None of these

1. Unit of pole strength is :

(a) N

(b) N/Am

(c) Am

(d) T

1. The magnetic moment of a steel rod of length ‘l’ is M . It is bent into a semi-circle . The new magnetic moment is :

(a) M

(b) 2Ml

(c) M/l

(d) 2M/π

1. A circular current loop is of magnetic moment M. if the radius of the current loop is halved the dipole moment will be :

(a) M

(b) M/2

(c) M/4

(d) 4M

1. A short bar magnet is placed with its south pole towards geographical north . The neutral points are situated at a distance of 20 cm from the centre of the magnet . If BH= 0.3 10-4Wb/m2, then the magnetic moment of the magnet is :

(a) 9 Am2

(b) 0.9 Am2

(c) 1.2 Am2

(d) 12 Am2

1. The angle between magnetic meridian and geographical meridian is called :

(a) Angle of dip

(b) declination

(c) Angle of polarization

(d) Critical angle

1. If the relative permeability of a matter is 0.9999 , then its nature is :

(a) Paramagnetic

(b) Diamagnetic

(c) Ferromagnetic

(d) Non-magnetic

1. The angle of dip at magnetic poles is :

(a) 45°

(b) 30°

(c) 0°

(d) 90°

1. The unit of magnetic dipole moment is :

(a) n/ampere metre

(b) A/m2

(c) Am2

(d) Wb/m2

1. The value of magnetic susceptibility is small but positive in case of :

(a) Paramagnetic substance

(b) Ferromagnetic substances

(c) diamagnetic substances

(d) All substances

1. The angle of dip at a place is 30. If the horizontal component of earth’s magnetic field be H, then the field intensity will be :

(a) H/2

(b) 2H/√3

(c) H√2

(d) H√3

1. Magnetic permeability of paramagnetic substances is :

(a) 0

(b) > 1

(c)  < 1

(d)  1

1. A conducting wire of length l metre is bent into a circular loop and I amp current is passed in it . The magnetic moment of the loop will be :

(a) Il2/4π

(b) Il2/2π

(c) πIl2

(d) Il

1. Relative permeability of ferromagnetic substances is :

(a) < 1

(b) 1

(c) > 1

(d) >> 1

1. Horizontal component of earth’s magnetic field is zero at :

(a) Magnetic poles

(b) Geographical poles

(c) Each place

(d) Magnetic equator

1. The coercivity of a small bar magnet is 4×103A/m . If it is inserted inside a solenoid of 500 turns and length 1 m to demagnetize it . The amount of current to be passed through the solenoid will be :

(a) 2.5 A

(b) 5 A

(c) 8 A

(d) 10 A

1. S.I. unit of magnetic moment is :

(a) IT-2

(b) Am-2

(c) IT

(d) Am-1

1. When the intensity of magnetic field is increased four times the time period of suspended magnetic needle becomes :

(a) Double

(b) half

(c) Four terms