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PHYSICS

This Physics category collects practice questions across the subject's main areas, from mechanics and thermodynamics to electricity, magnetism and modern physics. Questions mix conceptual reasoning with numerical problem solving, so you can test both your understanding of principles and your speed with calculations. Use it for topic-wise revision or timed practice before an exam.

45 questions

In an LCR circuit with R = 3 Ω, X_L = 8 Ω, X_C = 4 Ω, what is the power factor?

Given: In an LCR circuit with R = 3 Ω, X_L = 8 Ω, X_C = 4 Ω, what is the power factor? These values define the system as per NCERT data. Formula: Impedance: Z = sqrtR² + (X_L - X_C)² = sqrt3² + (8 - 4)² = sqrt9 + 16 = 5 Ω. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Power factor: cos phi = R/Z = 3/5 = 0.6 . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Current Electricity, Topic: Resistivity, temperature dependence and circuit analysis.

A rectangular loop of 0.24 m × 0.38 m moves out of a 0.3 T field at 0.6 m/s along its shorter side. What is the emf?

Given: A rectangular loop of 0.24 m × 0.38 m moves out of a 0.3 T field at 0.6 m/s along its shorter side. What is the emf? These values define the system as per NCERT data. Formula: varepsilon = B l v, l = 0.38 m. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: varepsilon = 0.3 × 0.38 × 0.6 = 0.0684 V approx 0.068 V . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Electromagnetic Induction, Alternating Current and Electromagnetic Waves, Topic: Induced emf, inductance and EM wave properties.

A dipole with m = 0.35 A m² in B = 0.9 T at 30° has torque:

Given: A dipole with m = 0.35 A m² in B = 0.9 T at 30° has torque: These values define the system as per NCERT data. Formula: tau = m B sinθ. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Given: m = 0.35 A m², B = 0.9 T, θ = 30°, sin 30° = 0.5 . tau = 0.35 × 0.9 × 0.5 = 0.1575 N m . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Moving Charges and Magnetism and Magnetism and Matter, Topic: Magnetic field due to current loop, solenoid and magnetic dipole moment. Page number should be added only after verification from the.

A rod rotates at 15 rad/s in a 0.3 T field. If the length from the axis to the tip is 0.4 m, what is the emf induced?

Given: A rod rotates at 15 rad/s in a 0.3 T field. If the length from the axis to the tip is 0.4 m, what is the emf induced? These values define the system as per NCERT data. Formula: varepsilon = 1/2 B omega R². This is the standard NCERT relation for this phenomenon. Substitution & Calculation: varepsilon = 1/2 × 0.3 × 15 × (0.4)² = 0.36 V . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Electromagnetic Induction, Alternating Current and Electromagnetic Waves, Topic: Induced emf, inductance and EM wave properties.

A spherical shell has a net flux of 1.13 × 10⁵ Nm²/C through it. What is the charge enclosed?

Given: A spherical shell has a net flux of 1.13 × 10⁵ Nm²/C through it. What is the charge enclosed? These values define the system as per NCERT data. Formula: phi = q/varepsilon_0. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: q = phi varepsilon_0 = 1.13 × 10⁵ × 8.854 × 10⁻¹²= 1.0 × 10⁻⁶ C = 1 μC . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Units and Measurements and Physical World, Topic: Dimensional analysis and fundamental principles.

A rectangular loop of area 0.05 m² with 16 turns carries 2.2 A in a field of 0.7 T at 45° to the plane. What is the to

Given: A rectangular loop of area 0.05 m² with 16 turns carries 2.2 A in a field of 0.7 T at 45° to the plane. What is the torque? These values define the system as per NCERT data. Formula: tau = N I A B sin θ, where θ = 45° to plane means sin 45° with normal. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: tau = 16 × 2.2 × 0.05 × 0.7 × sin 45° = 1.232 × 0.707 = 0.871 approx 0.87 N m . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Units and Measurements and Physical World, Topic: Dimensional analysis and fundamental principles.

Two identical springs ( k = 75 N/m ) are attached to a 1.5 kg mass as in Fig. 13.14. What is the frequency?

Given: Two identical springs ( k = 75 N/m ) are attached to a 1.5 kg mass as in Fig. 13.14. What is the frequency? These values define the system as per NCERT data. Formula: Effective k_{eff = 2k = 2 × 75 = 150 N/m. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: omega = sqrtfrack_{effm = sqrt150/1.5 = sqrt100 = 10 rad/s . v = omega/2π = 10/2 × 3.14 approx 1.59 Hz . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Oscillations and Waves, Topic: SHM, wave motion and superposition.

A 35 g bullet at 1200 m/s emerges from a block with 80% of its initial kinetic energy. What is its emergent speed?

Given: A 35 g bullet at 1200 m/s emerges from a block with 80% of its initial kinetic energy. What is its emergent speed? These values define the system as per NCERT data. Formula: Initial K = 1/2 × 0.035 × 1200² = 25200 J. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Final K = 0.8 × 25200 = 20160 J . 1/2 × 0.035 × v_f² = 20160 Rightarrow v_f² = 1152000 Rightarrow v_f = sqrt1152000 approx 1073.3 m/s . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Laws of Motion, Work Energy Power, Gravitation and System of Particles, Topic: Newton's laws, work-energy theorem and rotational dynamics.

A stone is dropped from a cliff 45 m high with an initial horizontal speed of 15 m/s. What is its speed on hitting the g

Given: A stone is dropped from a cliff 45 m high with an initial horizontal speed of 15 m/s. What is its speed on hitting the ground? (Take g = 10 m/s²) These values define the system as per NCERT data. Formula: Horizontal velocity: v_x = 15 m/s (constant). This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Vertical velocity: v_y = √(2gh) = √(2 × 10 × 45) = √900 = 30 m/s. Speed v = √(v_x² + v_y²) = √(15² + 30²) = √(225 + 900) = √1125 ≈ 33.54 m/s. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Units and Measurements and Physical World, Topic: Dimensional analysis and fundamental principles.

A Wheatstone bridge has R_1 = 14 Ω, R_2 = 28 Ω, R_3 = 10 Ω . What is R_4 for balance?

Given: A Wheatstone bridge has R_1 = 14 Ω, R_2 = 28 Ω, R_3 = 10 Ω . What is R_4 for balance? These values define the system as per NCERT data. Formula: Balance condition: R_1/R_2 = R_3/R_4. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Substitute: 14/28 = 10/R_4 . Solve: 0.5 = 10/R_4 Rightarrow R_4 = 10/0.5 = 20 Ω . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Units and Measurements and Physical World, Topic: Dimensional analysis and fundamental principles.

A glass slab ( n = 1.5 ) of thickness 7.5 cm is placed over a point. What is the apparent shift?

Given: A glass slab ( n = 1.5 ) of thickness 7.5 cm is placed over a point. What is the apparent shift? These values define the system as per NCERT data. Formula: Shift = t ( 1 - 1/n ). This is the standard NCERT relation for this phenomenon. Substitution & Calculation: t = 7.5 cm, n = 1.5 . Shift = 7.5 ( 1 - 1/1.5 ) = 7.5 ( 1 - 2/3 ) = 7.5 × 1/3 = 2.5 cm . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Units and Measurements and Physical World, Topic: Dimensional analysis and fundamental principles.

A circuit has a 6 V battery with 1 Ω internal resistance and two resistors 2 Ω and 3 Ω in parallel. What is the total

Given: A circuit has a 6 V battery with 1 Ω internal resistance and two resistors 2 Ω and 3 Ω in parallel. What is the total current? These values define the system as per NCERT data. Formula: Parallel resistance: 1/R_p = 1/2 + 1/3 = 3 + 2/6 = 5/6 Rightarrow R_p = 6/5 = 1.2 Ω. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Total resistance: R_{total = 1 + 1.2 = 2.2 Ω . Current: I = fracvarepsilonR_{total = 6/2.2 approx 2.73 A . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Current Electricity, Topic: Resistivity, temperature dependence and circuit analysis.