Electromagnetism
Current Electricity
MCQ (Single Correct Answer)
Moving Charges and Magnetism
MCQ (Single Correct Answer)
Magnetism and Matter
MCQ (Single Correct Answer)
Electromagnetic Induction
MCQ (Single Correct Answer)
Alternating Current
MCQ (Single Correct Answer)
Electromagnetic Waves
MCQ (Single Correct Answer)
Modern Physics
Dual Nature of Radiation
MCQ (Single Correct Answer)
Semiconductor Devices and Logic Gates
MCQ (Single Correct Answer)
Communication Systems
MCQ (Single Correct Answer)
1
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Two point charges $$20 \mu \mathrm{C}$$ and $$-10 \mu \mathrm{C}$$ are separated by a distance of $$1 \mathrm{~m}$$ in air. At what point on the line joining the two charges, the electric potential is zero.

A
$$0.5 \mathrm{~m}$$ from the charge $$10 \mu \mathrm{C}$$
B
$$0.76 \mathrm{~m}$$ from the charge $$20 \mu \mathrm{C}$$
C
$$0.67 \mathrm{~m}$$ from the charge $$20 \mu \mathrm{C}$$
D
$$0.25 \mathrm{~m}$$ from the charge $$10 \mu \mathrm{C}$$
2
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

A spherical metal ball of density '$$\rho$$' and radius '$$r$$' is immersed in a liquid of density '$$\sigma$$'. When an electric field is applied in the upward direction the metal ball remains just suspended in the liquid. Then the expression for the charge on the metal ball is :

A
$$q=\frac{\left[\frac{4}{3} \pi r^3 \rho g\right]}{\sigma E}$$
B
$$q=\frac{\left[4 \pi r^3(\rho-\sigma) g\right]}{3 E}$$
C
$$q=\frac{\left[4 \pi r^2 \rho g\right]}{\sigma E}$$
D
$$q=\frac{\left[4 \pi r^2(\rho-\sigma) g\right]}{E}$$
3
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

PQRS is square of side $$1 \mathrm{~m}$$. A charge of $$100 \mu \mathrm{C}$$ is placed at the centre of the square. Then the work done to take $$3 \mu \mathrm{C}$$ charge from the corner $$\mathrm{P}$$ to the corner $$\mathrm{R}$$.

A
$$9 \sqrt{2} \times 10^5 \mathrm{~J}$$
B
$$4.5 \times 10^5 \mathrm{~J}$$
C
Zero
D
$$1.8 \times 10^5 \mathrm{~J}$$
4
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

An electron and a proton having mass $$m_e$$ and $$m_p$$ respectively, initially at rest, move through the same distance '$$s$$' in a uniform electric field '$$E$$'. If the time taken by them to cover that distance is $$t_e$$ and $$t_p$$ respectively, then $$t_e / t_p$$ is equal to:

A
$$ \sqrt{\left(\frac{m_p}{m_e}\right)} $$
B
$$ \sqrt{\left(\frac{m_e}{m_p}\right)} $$
C
$$ \frac{\sqrt{\left(m_e\right)}}{m_p} $$
D
$$ \frac{m_e}{m_p} $$
COMEDK Subjects