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PHYSICS

This physics category collects practice questions covering the core areas of the subject, from mechanics and thermodynamics to electricity, magnetism and modern physics. Use it to revise concepts, get comfortable with numerical problems, and find the gaps in your preparation before test day.

45 questions

A material with susceptibility chi = -3 × 10⁻⁵ has a relative permeability μ_r of:

Given: A material with susceptibility chi = -3 × 10⁻⁵ has a relative permeability μ_r of: These values define the system as per NCERT data. Formula: μ_r = 1 + chi. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Given: chi = -3 × 10⁻⁵. Substitute: μ_r = 1 - 3 × 10⁻⁵= 0.99997 . 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 magnetic dipole experiences a torque of 0.02 N m in a field of 0.4 T at 90° . What is its magnetic moment?

Given: A magnetic dipole experiences a torque of 0.02 N m in a field of 0.4 T at 90° . What is its magnetic moment? These values define the system as per NCERT data. Formula: tau = m B sinθ, so m = tau/B sinθ. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Given: tau = 0.02 N m, B = 0.4 T, θ = 90°, sin 90° = 1 . m = 0.02/0.4 × 1 = 0.05 A m² . 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 spring of k = 180 N/m has a 0.9 kg mass. If E = 0.9 J, what is the amplitude?

Given: A spring of k = 180 N/m has a 0.9 kg mass. If E = 0.9 J, what is the amplitude? These values define the system as per NCERT data. Formula: Total energy: E = 1/2 k A². This is the standard NCERT relation for this phenomenon. Substitution & Calculation: 0.9 = 0.5 × 180 × A² Rightarrow 0.9 = 90 A² Rightarrow A² = 0.01 Rightarrow A = 0.1 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: Laws of Motion, Work Energy Power, Gravitation and System of Particles, Topic: Newton's laws, work-energy theorem and rotational dynamics.

A 7 kg block on a horizontal surface ( μ_k = 0.3 ) is pulled by a 4 kg mass over a pulley. A 14 N force opposes the 7 k

Given: A 7 kg block on a horizontal surface ( μ_k = 0.3 ) is pulled by a 4 kg mass over a pulley. A 14 N force opposes the 7 kg block. What is the acceleration? (Take g = 10 m/s² ) These values define the system as per NCERT data. Formula: For 4 kg : 4g - T = 4a Rightarrow 40 - T = 4a. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: For 7 kg : T - f_k - 14 = 7a . Normal: N = mg = 7 × 10 = 70 N . Friction: f_k = 0.3 × 70 = 21 N . Net force: T - 21 - 14 = 7a Rightarrow T - 35 = 7a . Solve: 40 - T = 4a, T - 35 = 7a . Substitute: 40 - (7a + 35) = 4a Rightarrow 40 - 35 - 7a = 4a Rightarrow 5 = 11a . a = 5/11 approx 0.45 m/s² . 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 coil of 80 turns is placed in a magnetic field that increases from 0 to 0.03 Wb/m² in 0.2 s. If the coil area is 0.05

Given: A coil of 80 turns is placed in a magnetic field that increases from 0 to 0.03 Wb/m² in 0.2 s. If the coil area is 0.05 m², what is the induced emf? These values define the system as per NCERT data. Formula: Flux change: Δ Phi = B A = 0.03 × 0.05 = 0.0015 Wb. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: varepsilon = N Δ Phi/Δ t = 80 × 0.0015/0.2 = 80 × 0.0075 = 0.6 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: 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 gas mixture contains 4 g of helium and 32 g of oxygen. What is the total pressure if the volume is 22.4 litres at 273

Given: A gas mixture contains 4 g of helium and 32 g of oxygen. What is the total pressure if the volume is 22.4 litres at 273 K? (R = 8.31 J mol^{-1 K^{-1) These values define the system as per NCERT data. Formula: μ_{He = 4/4 = 1 mol, μ_{O_2 = 32/32 = 1 mol. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Total moles = 1 + 1 = 2 mol, V = 22.4 × 10⁻³ m³. P = μ R T/V = frac2 × 8.31 × 27322.4 × 10⁻³= 2.02 × 10⁵ Pa approx 2 atm . 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 wire of length 6 m and cross-sectional area 5 × 10⁻⁶ m² has a resistance of 12 Ω . What is the resistivity of t

Given: A wire of length 6 m and cross-sectional area 5 × 10⁻⁶ m² has a resistance of 12 Ω . What is the resistivity of the material? These values define the system as per NCERT data. Formula: Resistance: R = rho l/A. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Rearrange: rho = R A/l . Substitute: rho = frac12 × 5 × 10⁻⁶⁶= 10 × 10⁻⁶= 1.0 × 10⁻⁵Ω 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: Current Electricity, Topic: Resistivity, temperature dependence and circuit analysis.

A steel rod has a length of 1 m at 20° C . What will be its length at 120° C if the coefficient of linear expansion of

Given: A steel rod has a length of 1 m at 20° C . What will be its length at 120° C if the coefficient of linear expansion of steel is 1.2 × 10⁻⁵ K^{-1 ? These values define the system as per NCERT data. Formula: Given: L_0 = 1 m, T_1 = 20° C, T_2 = 120° C, α_l = 1.2 × 10⁻⁵ K^{-1. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Δ T = 120 - 20 = 100° C . Linear expansion: Δ L = L_0 α_l Δ T = 1 × 1.2 × 10⁻⁵ × 100 = 1.2 × 10⁻³ m . New length: L = L_0 + Δ L = 1 + 0.0012 = 1.0012 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.

A wire of length 0.6 m carrying 9 A is at 60° to a magnetic field of 0.4 T . What is the force on the wire?

Given: A wire of length 0.6 m carrying 9 A is at 60° to a magnetic field of 0.4 T . What is the force on the wire? These values define the system as per NCERT data. Formula: F = I l B sin θ. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: F = 9 × 0.6 × 0.4 × sin 60° = 2.16 × 0.866 = 1.8706 approx 1.87 N . 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 photon’s energy is 3.0 eV . What is its momentum? (Take c = 3 × 10⁸ m/s, 1 eV = 1.6 × 10⁻¹⁹ J )

Given: A photon’s energy is 3.0 eV . What is its momentum? (Take c = 3 × 10⁸ m/s, 1 eV = 1.6 × 10⁻¹⁹ J ) These values define the system as per NCERT data. Formula: E = 3.0 × 1.6 × 10⁻¹⁹= 4.8 × 10⁻¹⁹ J. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: For a photon, p = E/c = frac4.8 × 10⁻¹⁹³ × 10⁸= 1.6 × 10⁻²⁷ kg 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 dipole p = 6 × 10⁻⁹ C m is rotated from θ = 0° to 90° in a field E = 3 × 10⁵ N/C . What is the work done?

Given: A dipole p = 6 × 10⁻⁹ C m is rotated from θ = 0° to 90° in a field E = 3 × 10⁵ N/C . What is the work done? These values define the system as per NCERT data. Formula: Work done: W = p E (cos θ_0 - cos θ_1) = 6 × 10⁻⁹ × 3 × 10⁵ × (cos 0° - cos 90°). This is the standard NCERT relation for this phenomenon. Substitution & Calculation: W = 6 × 10⁻⁹ × 3 × 10⁵ × (1 - 0) = 1.8 × 10⁻³ J . 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.

An electron moves with a speed of 2 × 10⁶ m/s perpendicular to a magnetic field of 0.7 T . What is the radius of its

Given: An electron moves with a speed of 2 × 10⁶ m/s perpendicular to a magnetic field of 0.7 T . What is the radius of its path? (Mass = 9.1 × 10⁻³¹ kg, charge = 1.6 × 10⁻¹⁹ C ) These values define the system as per NCERT data. Formula: Radius r = mv/qB. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: r = frac9.1 × 10⁻³¹ × 2 × 10⁶¹.6 × 10⁻¹⁹ × 0.7 = frac1.82 × 10⁻²⁴¹.12 × 10⁻¹⁹= 1.625 × 10⁻⁵ m = 1.625 × 10⁻³ 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: 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.