1
COMEDK 2026 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

A circular coil of radius $r=10 c m$ having 300 turns carries a current of 2 A . The coil is suspended vertically in a uniform magnetic field of strength 0.7 T . If the plane of the coil makes an angle $30^{\circ}$ with the magnetic field, the torque needed to prevent it from turning is:

A

11.42 Nm

B

1.1 Nm

C

22.84 Nm

D

5.71 Nm

2
COMEDK 2026 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

The width of the fringes obtained with a light of wave length $6.2 \times 10^{-8} \mathrm{~m}$ is 1.82 mm . If the whole apparatus is immersed in a liquid of refractive index 1.3 , what will be the width of the resulting fringe?

A

1.4 mm

B

0.71 mm

C

2.8 mm

D

1.82 mm

3
COMEDK 2026 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

If $\mu_0$ is the permeability of free space and $\varepsilon_0$ permittivity of free space then the dimension for $\left(\mu_0 \varepsilon_0\right)^{1 / 2}$ is :

A

$\left[M L^{-1} T\right]$

B

$\left[M L T^{-1}\right]$

C

$\left[L^{-1} T\right]$

D

$\left[L^{-1} T^{-1}\right]$

4
COMEDK 2026 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

An electric field and magnetic field $1.8 \times 10^4 \mathrm{Vm}^{-1}$ and $6 \times 10^{-3} \mathrm{~T}$ respectively are applied simultaneously on an electron beam such that path of the beam remains undeviated, then the speed of the electron will be:

A

$1.5 \times 10^6 \mathrm{~ms}^{-1}$

B

$3 \times 10^7 \mathrm{~ms}^{-1}$

C

$3 \times 10^6 \mathrm{~ms}^{-1}$

D

$1.5 \times 10^7 \mathrm{~ms}^{-1}$