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

A charge of $5 \mu \mathrm{C}$ is placed at the centre of a spherical shell $S_1$ of radius 10 cm . Now this system is enclosed inside another spherical shell $S_2$ of radius 20 cm . The ratio of the electrical flux through the surface $S_2$ to $S_1$ is :

A

$1: 2$

B

$4:1$

C

$2:1$

D

$1: 1$

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

The main function of cadmium used in the nuclear reactor is:

A

It removes the heat produced at the core of the reactor

B

It gives energy to the secondary neutrons produced in the nuclear fission

C

It slows down the fast moving secondary neutrons produced during the nuclear fission

D

To capture the slow neutron produced in the nuclear reactor

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

What is the frequency of the electron in the first orbit of hydrogen atom of orbital radius $0.5 \times 10^{-10} \mathrm{~m}$, if its orbital velocity in that orbit is $2.2 \times 10^6 \mathrm{~ms}^{-1}$.

A

$3.49 \times 10^{15} \mathrm{~Hz}$

B

$3.49 \times 10^{13} \mathrm{~Hz}$

C

$6.98 \times 10^{15} \mathrm{~Hz}$

D

$6.98 \times 10^{13} \mathrm{~Hz}$

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

An object is dropped from a certain point A at a height ' h ' from the ground. During it's journey straight downwards, the object passes points $B$ and $C$ such that the ratio of time taken $t_1$ to cover $A B$ and $t_2$ to cover $B C$ is $1:(\sqrt{2}-1)$. What is the ratio of distances $A B: B C$ ?

A

$1: 1$

B

$(\sqrt{2}-1): 1$

C

$1: \sqrt{2}$

D

$\sqrt{2}: 1$