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

A pith ball of mass ' $m$ ' gram and charge ' $Q$ ' is suspended using a mass less silk thread near a large charged conducting metal sheet of area ' $A$ ' and surface charged density ' $\sigma$ '. If the silk thread makes an angle $\Theta$ with the metal sheet, then:

A

$\tan \theta \propto \sigma$

B

$\tan \theta \propto A$

C

$\tan \theta \propto m g$

D

$\tan \theta \propto \frac{1}{\sigma}$

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

The material selected for making a permanent magnet should have:

A

High coercivity, low permeability and high retentivity

B

Low coercivity, low permeability and low retentivity

C

Low coercivity, low permeability and high retentivity

D

High coercivity, high permeability and high retentivity

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

Calculate the vapour pressure that can help the formation of a spherical droplet of water of radius $6.25 \times 10^{-5} \mathrm{~m}$ at $22^{\circ} \mathrm{C}$. Given: The surface tension of water at the given temperature is $7.28 \times 10^{-2} \mathrm{Nm}^{-1}$.

A

$1.01 \times 10^5 \mathrm{~Pa}$

B

$2.33 \times 10^3 \mathrm{~Pa}$

C

$8.81 \times 10^3 \mathrm{~Pa}$

D

$6.64 \times 10^4 \mathrm{~Pa}$

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

The atomic mass of an element $10 X^{20}$ is 19.98170 amu. The binding energy per nucleon of that element is: [given mass of neutron = 1.00867amu and mass of proton = 1.00783 amu and 1amu = 931 MeV ]

A

$17.66 \mathrm{MeV} /$ nucleon

B

$ 8.533 MeV /$ nucleon

C

$85.33 \mathrm{MeV} /$ nucleon

D

$170.66 \mathrm{MeV} /$ nucleon