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197 questions found · practise this subject as a set Show 20 · 50 per page

#	Question	Subject and topic	Difficulty
1	What is the SI unit of electric charge?	Physics Electric charge and Coulomb’s law	Easy
2	A current of 2 A flows through a resistor of 10 Ω. What is the potential difference across it?	Physics Ohm’s law and resistance	Easy
3	What is the power of a convex lens of focal length 0.5 m?	Physics Lenses	Easy
4	Who explained the photoelectric effect using the idea of light quanta (photons)?	Physics Photoelectric effect	Easy
5	Two 4 Ω resistors are connected in parallel. What is the equivalent resistance?	Physics Cells, emf and internal resistance	Easy
6	What is the approximate speed of light in vacuum?	Physics Electromagnetic spectrum	Easy
7	What is the SI unit of magnetic field (magnetic flux density)?	Physics Biot-Savart law	Easy
8	Two point charges of 2 μC and 3 μC are placed 0.3 m apart in vacuum. The force between them is:	Physics Electric charge and Coulomb’s law	Easy
9	If the distance between two point charges is halved, the Coulomb force between them becomes:	Physics Electric charge and Coulomb’s law	Easy
10	How many electrons together carry a total charge of magnitude 1 C?	Physics Electric charge and Coulomb’s law	Medium
11	A glass rod rubbed with silk becomes positively charged because:	Physics Electric charge and Coulomb’s law	Medium
12	Two charges exert a force of 8 N on each other in air. When placed at the same separation in a medium of diel…	Physics Electric charge and Coulomb’s law	Hard
13	The electric field at a distance of 0.2 m from a point charge of 4 nC in vacuum is:	Physics Electric field and dipoles	Easy
14	An electric dipole of moment 2 × 10⁻⁸ C m is placed at 30° to a uniform field of 5 × 10⁴ N/C. The torque on i…	Physics Electric field and dipoles	Medium
15	A dipole placed in a uniform electric field experiences:	Physics Electric field and dipoles	Easy
16	At large distances, the electric field of a short dipole varies with distance r as:	Physics Electric field and dipoles	Medium
17	At the same large distance from a short dipole, the ratio of the axial field to the equatorial field is:	Physics Electric field and dipoles	Hard
18	A closed surface encloses a net charge of 8.85 nC. The total electric flux through it is about:	Physics Gauss’s theorem	Easy
19	The electric field inside a uniformly charged thin spherical shell is:	Physics Gauss’s theorem	Easy
20	A very long straight wire carries a uniform charge of 2 μC per metre. The field at 0.1 m from it is about:	Physics Gauss’s theorem	Medium
21	The electric field due to an infinite plane sheet of uniform charge density σ:	Physics Gauss’s theorem	Medium
22	A charge q is placed at the centre of a cube. The electric flux through any one face of the cube is:	Physics Gauss’s theorem	Hard
23	The electric potential at a distance of 0.5 m from a point charge of 5 nC is:	Physics Electric potential	Easy
24	The work done in moving a charge of 2 μC between two points with a potential difference of 50 V is:	Physics Electric potential	Easy
25	The angle between electric field lines and an equipotential surface is always:	Physics Electric potential	Medium
26	The electrostatic potential energy of charges 1 μC and 2 μC kept 0.1 m apart in vacuum is:	Physics Electric potential	Medium
27	At the midpoint of the line joining two equal and opposite charges, which statement is correct?	Physics Electric potential	Hard
28	Inside a charged metal conductor in electrostatic equilibrium, the electric field is:	Physics Conductors, dielectrics and polarisation	Easy
29	Excess charge given to an isolated conductor resides:	Physics Conductors, dielectrics and polarisation	Easy
30	When a dielectric slab is placed in an external electric field, the field inside the slab:	Physics Conductors, dielectrics and polarisation	Medium
31	Which of the following molecules is polar?	Physics Conductors, dielectrics and polarisation	Medium
32	A person sitting inside a closed metal car is safe from a lightning strike mainly because of:	Physics Conductors, dielectrics and polarisation	Hard
33	Capacitors of 2 μF and 3 μF are connected in series. The equivalent capacitance is:	Physics Capacitors	Easy
34	The energy stored in a 10 μF capacitor charged to 100 V is:	Physics Capacitors	Easy
35	A parallel plate capacitor has plates of area 0.02 m² separated by 1 mm of air. Its capacitance is about:	Physics Capacitors	Medium
36	The space between the plates of an air capacitor is completely filled with a dielectric of constant 5. Its ca…	Physics Capacitors	Medium
37	A capacitor is charged by a battery and then disconnected. If the plate separation is now doubled, the stored…	Physics Capacitors	Hard
38	A steady current of 2 A flows in a wire for 5 minutes. The charge that passes through any cross-section is:	Physics Electric current and drift velocity	Easy
39	A copper wire of cross-section 1 mm² carries 1.5 A. If n = 8.5 × 10²⁸ m⁻³, the drift speed of electrons is ab…	Physics Electric current and drift velocity	Medium
40	The SI unit of electron mobility is:	Physics Electric current and drift velocity	Medium
41	A bulb lights up almost instantly when switched on, although the drift speed of electrons is very small. This…	Physics Electric current and drift velocity	Easy
42	A steady current flows through a wire whose radius at end X is twice the radius at end Y. The ratio of drift …	Physics Electric current and drift velocity	Hard
43	The resistance of a copper wire of length 10 m and cross-section 1 mm² (ρ = 1.7 × 10⁻⁸ Ω m) is:	Physics Ohm’s law and resistance	Easy
44	A uniform wire is stretched to twice its original length. Its resistance becomes:	Physics Ohm’s law and resistance	Medium
45	The resistivity of a metal wire depends on:	Physics Ohm’s law and resistance	Easy
46	A metal wire has resistance 10 Ω at 0 °C and temperature coefficient 0.004 °C⁻¹. Its resistance at 100 °C is:	Physics Ohm’s law and resistance	Medium
47	As the temperature of a pure semiconductor rises, its resistivity:	Physics Ohm’s law and resistance	Hard
48	The resistance of the filament of a bulb rated 100 W, 220 V is:	Physics Electrical energy and power	Easy
49	A 100 W, 220 V bulb is connected to a 110 V supply. Assuming constant resistance, it consumes:	Physics Electrical energy and power	Medium
50	A 1000 W heater is used for 3 hours. The energy consumed is:	Physics Electrical energy and power	Easy