MCQ Questions for Class 12 Physics Chapter 5 Magnetism and Matter with Answers

  

Magnetism and Matter Class 12 MCQs Questions with Answers

Question 1.
S.I. unit of flux is :
(a) Ohm
(b) Weber
(c) Tesla
(d) None

Answer

Answer: (b) Weber

---

Question 2.
What is the angle of dip at a place where the horizontal component of earth’s magnetic field is equal to the vertical component?
(a) 0°
(b) 30°
(c) 45°
(d) 90°

Answer

Answer: (c) 45°

---

Question 3.
Which of the following has a low value in ferrites?
(a) Conductivity
(b) Permeability
(c) Magnetic susceptibility
(d) All the above

Answer

Answer: (a) Conductivity

---

Question 4.
The dimensional representation of magnetic flux density is :
(a) [MLT-2]
(b) [MLT-2A-1]
(c) [MLT-2A-2]
(d) [MT-2A-1]

Answer

Answer: (d) [MT-2A-1]

---

Question 5.
Tangent law is applicable only when:
(a) two uniform and mutually perpendicular magnetic fields exist
(b) two magnetic fields exist
(c) horizontal component of earth’s magnetic field is present
(d) uniform magnetic field are used

Answer

Answer: (a) two uniform and mutually perpendicular magnetic fields exist

---

Question 6.
Ferrites may be:
(a) ant. ferromagnetic
(b) ferromagnetic
(c) ferrimagnetic
(d) None of the above

Answer

Answer: (b) ferromagnetic

---

Question 7.
A magnetic bar of M magnetic moment is placed m the field of magnetic strength B, the torque acting on it is :
(a) M⃗ .B⃗ 
(b) –M⃗ .B⃗ 
(c) M⃗  × B⃗ .
(d) B⃗  × M⃗ 

Answer

Answer: (c) M⃗  × B⃗ .

---

Question 8.
The magnetic lines of force inside a bar magnet:
(a) do not exist
(b) depends on area of cross-section of bar magnet
(c) are from N-pole to S-pole of the magnet
(d) are from S-pole to N-pole of the magnet.

Answer

Answer: (d) are from S-pole to N-pole of the magnet.

---

Question 9.
A magnetic dipole moment is a vector quantity directed from:
(a) S to N
(b) N to S
(c) E to W
(d) W to E

Answer

Answer: (a) S to N

---

Question 10.
What is the magnetic field in the empty space enclosed by the toroidal solenoid of radius ‘R’? ,
(a) Infinity
(b) µ04π.2πlR
(c) µ04π.(πlR)
(d) zero

Answer

Answer: (d) zero

---

Question 11.
A current carrying power line carries current from west to east. What will be direction of magnetic field 1 meter above it?
(a) N to S
(b) S to N
(c) E to W
(d) W to E

Answer

Answer: (a) N to S

---

Question 12.
The dimensional representation of l/MB−−−−−√ is similar to that of:
(a) frequency
(b) time
(c) distance
(d) speed

Answer

Answer: (b) time

---

Question 13.
On quadrupling the moment of inertia of a magnet, its frequency of oscillation will become:
(a) half
(b) double
(c) four times
(d) one-fourth

Answer

Answer: (a) half

---

Question 14.
The magnetic field strength due to a short bar magnet directed along its axial line at a distance r is B. What is its value at the same distance along the equatorial line?
(a) B
(b) 2B
(c) B2
(d) B4

Answer

Answer: (c) B2

---

Question 15.
The neutral point in the magnetic field of a horizontally placed bar magnet is a point where the magnetic field due to that bar magnet is:
(a) zero
(b) more than that of earth
(c) less than that of earth
(d) equal to that of earth

Answer

Answer: (d) equal to that of earth

---

Question 16.
In a moving coil galvanometer, we use a radial magnetic field so that the galvanometer scale is :
(a) exponential
(b) linear
(c) algebraic
(d) logarithmic

Answer

Answer: (b) linear

---

Question 17.
The force between two parallel wire 2 × 10-7 Nm-1, placed 1 m apart to each other in vacuum. The electric current flowing through the wires is:
(a) 1 A
(b) zero
(c) 5 × 106 A
(d) 2 × 10-7 A

Answer

Answer: (a) 1 A

---

Question 18.
The force acting per unit length of a semi circular wire of radius R carrying a current I is:
(a) µ0l24R
(b) µ0l22R
(c) µ0l2R
(d) 2µ0l2R

Answer

Answer: (a) µ0l24R

---

Question 19.
Which of the following has higher magnetic susceptibility?
(a) diamagnetic
(b) paramagnetic
(c) ferromagnetic
(d) None of these

Answer

Answer: (c) ferromagnetic

---

Question 20.
The magnetic field of earth is due to:
(a) induction effect of the sun
(b) the presence of a large magnet at the centre of the earth
(c) interaction of cosmic rays with the current of earth
(d) motion and distribution of some material in an outside the earth

Answer

Answer: (d) motion and distribution of some material in an outside the earth

---

Question 21.
In a bar magnet, magnetic lines of force z :
(a) are produced only at north pole like rays of light from a bulb
(b) starts from north pole and ends at the south pole
(c) emerge in circular paths from the middle of the bar
(d) run continuously through the bar and outside

Answer

Answer: (b) starts from north pole and ends at the south pole

---

Question 22.
The Mariner’s compass is provided with Gimbals arrangement so as to :
(a) keep the needle always horizontal
(b) give a direct reading of declination
(c) give the direct value of dip
(d) all of the above

Answer

Answer: (c) give the direct value of dip

---

Question 23.
A wire of length I has a magnetic moment M. It is then bent into a semi-circular arc. The neyv magnetic moment is :
(a) M
(b) M.l.
(c) 2Mπ
(d) Mπ

Answer

Answer: (c) 2Mπ

---

Question 24.
The relation between geometric length (L) and magnetic length (Lm) is:
(a) Lm = 56 Lg
(b) Lm = 65 Lg
(c) (a) Lm = Lg
(d) Lm = 2RY;UL Lg

Answer

Answer: (a) Lm = 56 Lg

---

Question 25.
The radius of curvature of the path of charged particle in a uniform magnetic file is directly proportional to the
(a) charge on fie particle
(b) Momentum of particle
(c) energy of particle
(d) Strength of field

Answer

Answer: (b) Momentum of particle

---

Question 26.
The magnetic field at the centre of a current carrying circular loop is B. If the radius of the loop is doubled keeping the current unchanged, the magnetic field at the centre of loop will become:
(a) B2
(b) B4
(c) 2B
(d) 4B

Answer

Answer: (b) B4

---