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

Resonance is produced between a turning fork and a resonance column tube with upper end open and lower end closed by water surface. If the frequency of the tuning fork is 800 Hz , and first two resonances are observed at lengths $9.75 \mathrm{~cm}, 31.25 \mathrm{~cm}$,

Find the length at which the third resonance occurs? Also find the speed of sound.

A

52.75 cm and $344 \mathrm{~ms}^{-1}$

B

31.25 and $330 \mathrm{~ms}^{-1}$

C

62.60 cm and $335 \mathrm{~ms}^{-1}$

D

43.10 cm and $340 \mathrm{~ms}^{-1}$

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

A boy, standing at a certain height, kicks a football horizontally with a velocity of $19.6 \mathrm{~ms}^{-1}$. What will be the ratio of horizontal and vertical components of velocities after $2 s$ ?

A

$1: \sqrt{2}$

B

$\left(\frac{\sqrt{3}}{2}\right): 1$

C

$1: 1$

D

$ 1:0.5$

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

A capacitor of capacitance $8 \mu \mathrm{~F}$ is fully charged by connecting it to a source of 200 V . It is then disconnected from the supply and connected to an uncharged capacitor of capacitance $4 \mu \mathrm{~F}$. The electrostatic energy lost in this sharing is:

A

$21.34 \times 10^{-2} J$

B

$5.33 \times 10^{-2} J$

C

$3.53 \times 10^{-3} J$

D

$10.67 \times 10^{-2} J$

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

A hydrogen atom absorbs energy and rises to $n=3$ state from its ground state $n=1$. If the potential energy of the atom at its ground state is -13.6 eV , find the wave length emitted by it when it returns to its ground state:

{Planck's constant $=6.6 \times 10^{34} \mathrm{~J} \mathrm{~s}$ }

A

$12000^{\circ} \mathrm{A}$

B

$1020^{\circ} \mathrm{A}$

C

$7000^{\circ} \mathrm{A}$

D

$4000^{\circ} \mathrm{A}$