Free NEET Physics MCQs – NTA Syllabus Practice
Free NEET Physics MCQs | MCQAdda — Practice Questions
1. Two blocks of masses 2 kg and 4 kg are connected by a light string and pulled by a horizontal force of 18 N on a frictionless surface. The tension in the string is:
- (A) 6 N
- (B) 12 N
- (C) 9 N
- (D) 18 N
Answer: (A) 6 N
Acceleration = 18/(2+4) = 3 m/s². Tension = 2 × 3 = 6 N.
2. A convex lens has a focal length of 20 cm. An object is placed at 40 cm from the lens. The image formed is:
- (A) Virtual and magnified
- (B) Real, inverted and same size
- (C) Real and diminished
- (D) Virtual and diminished
Answer: (B) Real, inverted and same size
An object placed at 2F forms a real, inverted image of the same size at 2F.
3. In Young's double-slit experiment, the fringe width is increased by:
- (A) Decreasing wavelength
- (B) Increasing slit separation
- (C) Increasing screen distance
- (D) Decreasing screen distance
Answer: (C) Increasing screen distance
Fringe width β = λD/d. Increasing the screen distance increases the fringe width.
4. A body is projected vertically upward with an initial speed u. Ignoring air resistance, the average velocity during the entire journey is:
- (A) u/2
- (B) Zero
- (C) u
- (D) u/4
Answer: (B) Zero
The displacement for the complete upward and downward journey is zero. Therefore, average velocity is zero.
5. The magnetic field at the center of a circular current-carrying loop is directly proportional to:
- (A) Radius
- (B) Radius²
- (C) Current
- (D) Resistance
Answer: (C) Current
The magnetic field at the center of a circular loop is B = μ₀I/(2R), so it is directly proportional to current.
6. The work function of a metal is 2.2 eV. Photoelectric emission will occur only if the incident photon energy is:
- (A) Less than 2.2 eV
- (B) Equal to zero
- (C) Greater than or equal to 2.2 eV
- (D) Independent of work function
Answer: (C) Greater than or equal to 2.2 eV
The incident photon must have energy at least equal to the work function for photoelectric emission.
7. Two capacitors of capacitances 4 μF and 6 μF are connected in series. Their equivalent capacitance is:
- (A) 2.4 μF
- (B) 10 μF
- (C) 5 μF
- (D) 24 μF
Answer: (A) 2.4 μF
Ceq = (C₁C₂)/(C₁+C₂) = (4×6)/(4+6) = 2.4 μF.
8. The electric field inside a hollow conducting sphere in electrostatic equilibrium is:
- (A) Maximum at the center
- (B) Uniform but non-zero
- (C) Zero everywhere
- (D) Depends on the radius
Answer: (C) Zero everywhere
In electrostatic equilibrium, the electric field inside a conductor is zero.
9. A copper wire is stretched to twice its original length while maintaining constant volume. The resistance becomes:
- (A) R
- (B) 2R
- (C) 4R
- (D) 8R
Answer: (C) 4R
With constant volume, the cross-sectional area becomes half. Therefore, R ∝ L/A, giving R' = 4R.
10. An ideal gas expands isothermally. During the process:
- (A) Internal energy increases
- (B) Internal energy decreases
- (C) Internal energy remains constant
- (D) Temperature decreases
Answer: (C) Internal energy remains constant
Internal energy of an ideal gas depends only on temperature, which remains constant during an isothermal process.
11. A radioactive sample has an initial activity of 800 Bq. If its half-life is 10 hours, the activity after 30 hours will be:
- (A) 100 Bq
- (B) 200 Bq
- (C) 300 Bq
- (D) 400 Bq
Answer: (A) 100 Bq
Thirty hours correspond to three half-lives. Activity becomes 800 × (1/2)³ = 100 Bq.
12. A ray of light enters from air into glass. Which quantity remains unchanged?
- (A) Speed
- (B) Wavelength
- (C) Frequency
- (D) Refractive index
Answer: (C) Frequency
Frequency remains constant during refraction, while speed and wavelength change.
13. According to Lenz's law, the direction of induced current is such that it:
- (A) Supports the change producing it
- (B) Opposes the change producing it
- (C) Is always clockwise
- (D) Is always anticlockwise
Answer: (B) Opposes the change producing it
Lenz's law states that the induced current opposes the change in magnetic flux that produces it.
14. The escape speed from a planet depends on:
- (A) Mass of the projectile only
- (B) Radius of the planet only
- (C) Mass and radius of the planet
- (D) Density of the atmosphere
Answer: (C) Mass and radius of the planet
Escape speed is given by v = √(2GM/R), where M is the planet's mass and R is its radius.
15. Two sound waves of frequencies 256 Hz and 260 Hz are superposed. The beat frequency is:
- (A) 2 Hz
- (B) 4 Hz
- (C) 256 Hz
- (D) 516 Hz
Answer: (B) 4 Hz
Beat frequency is equal to the absolute difference in frequencies: |260 − 256| = 4 Hz.
16. A satellite revolves around the Earth in a circular orbit. Which quantity remains constant throughout its motion?
- (A) Velocity
- (B) Momentum
- (C) Kinetic energy
- (D) Acceleration
Answer: (C) Kinetic energy
The speed remains constant in uniform circular motion; hence kinetic energy remains constant, while velocity and momentum continuously change direction.
17. The time period of a simple pendulum is doubled. The new length of the pendulum becomes:
- (A) 2L
- (B) 4L
- (C) L/2
- (D) L/4
Answer: (B) 4L
Since T ∝ √L, doubling the time period requires the length to become four times.
18. In simple harmonic motion, acceleration is maximum when the particle is at:
- (A) Mean position
- (B) One-fourth amplitude
- (C) Extreme position
- (D) Half amplitude
Answer: (C) Extreme position
Acceleration in SHM is proportional to displacement and is maximum at the extreme positions.
19. In a p-type semiconductor, the majority charge carriers are:
- (A) Electrons
- (B) Holes
- (C) Protons
- (D) Neutrons
Answer: (B) Holes
Trivalent doping creates holes, making them the majority charge carriers.
20. A transformer operates on the principle of:
- (A) Electrostatic induction
- (B) Self-induction
- (C) Mutual induction
- (D) Coulomb's law
Answer: (C) Mutual induction
A transformer transfers electrical energy between coils through mutual induction.