Physics Test 198

Result

Physics Test 198

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Weekly Quiz Competition

Question 1
4 / -1

Shown in the figure is a meter-bridge set up with null deflection in the galvanometer. The value of the unknown resistor R is

A
13.75 Ω

B
220 Ω

C
110 Ω

D
55 Ω

Solution
Question 2
4 / -1

Constant current is flowing through a linear conductor of non-uniform area of cross-section. The charge flowing per second through the area of conductor at any cross-section is

A
Proportional to the area of cross-section

B
Inversely proportional to the area of cross-section

C
Independent of the area of cross-section

D
Dependent on the length of conductor

Solution

The quantity of charge flowing through any cross-section per second is defined as Current.

And as it is given that, Current through the conductor is constant so it will be same throughout irrespective of the cross-section area.

Hence, the charge flowing per second will be independent of the area of cross-section.
Question 3
4 / -1

A meter bridge is used to determine the resistance of an unknown wire by measuring the balance point length l. If the wire is replaced by another wire of same material but with double the length and half the thickness, the balancing point is expected to be

A
1 / 8l

B
1 / 4l

C
8l

D
16l

Solution

In a meter bridge the ratio of two resistances is

Therefore, the new balancing point is expected to be 8l.
Question 4
4 / -1

Potential difference between points A and B (i.e. V_A - V_B) is

A
4 V

B
2 V

C
6 V

D
8 V

Solution
Question 5
4 / -1

When the switches are arranged so that the current through the battery is maximum, what is the voltage across points A and B-

A
4 V

B
0 V

C
1 V

D
2 V

Solution
Question 6
4 / -1

The dimensions [MLT⁻²A⁻²] belong to the

A
Magnetic flux

B
Self inductance

C
Magnetic permeability

D
Electric permittivity

Solution

Dimensional formula of magnetic permeability is [MLT⁻²A⁻²]
Question 7
4 / -1

A uniform conducting wire of length 12a and resistance 'R' is wound up as a current carrying coil in the shape of,

(i) an equilateral triangle of side 'a'.

(ii) a square of side 'a'.

The magnetic dipole moments of the coil in each case respectively are

A
3 Ia² and 3 Ia²

B
3 Ia² and Ia²

C
3 Ia² and 4 Ia²

D
4 Ia² and 3 Ia²

Solution

Current in the loop will be V/R = l which is same for both loops.
Question 8
4 / -1

The magnetic field B on the axis of a circular coil at distance x far away from its centre are related as:

A
Bαx^-1

B
Bαx^-4

C
Bαx^-3

D
Bαx^-2

Solution
Question 9
4 / -1

The magnetic susceptibility is negative for

A
ferromagnetic material only

B
paramagnetic and ferromagnetic materials

C
diamagnetic material only

D
paramagnetic material only

Solution

Magnetic susceptibility is negative for diamagnetic material only.
Question 10
4 / -1

A rectangular coil of length 0.12 m and width 0.1 m having 50 turns of wire is suspended vertically in a uniform magnetic field of strength 0.2Weber/m². The coil carries a current of 2 A. If the plane of the coil is inclined at an angle of 30° with the direction of the field, the torque required to keep the coil in stable equilibrium will be

A
0.24 Nm

B
0.12 Nm

C
0.15 Nm

D
0.20 Nm

Solution

The required torque is τ = NIABsinθ

where N is the number of turns in the coil, I is the current through the coil, B is the uniform magnetic field, A is the area of the coil and 0 is the angle between the direction of the magnetic field and normal to the plane of the coil.