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PHYSICS

This category covers physics questions on motion and forces, energy, circuits, optics and related topics. Questions mix conceptual reasoning with numerical work, so you get practice at both. Use the answers to check where a calculation or assumption went wrong before moving to the next topic.

45 questions

What is the approximate mass number of a nucleus with radius 4.8 × 10⁻¹⁵ m ? (Given R_0 = 1.2 × 10⁻¹⁵ m )

Given: What is the approximate mass number of a nucleus with radius 4.8 × 10⁻¹⁵ m ? (Given R_0 = 1.2 × 10⁻¹⁵ m ) These values define the system as per NCERT data. Formula: R = R_0 A^{1/3. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: 4.8 × 10⁻¹⁵= 1.2 × 10⁻¹⁵ × A^{1/3 . A^{1/3 = 4.8/1.2 = 4 . A = 4³ = 64 . 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: Dual Nature, Atoms, Nuclei and Electronic Devices, Topic: Atomic structure, nuclear binding and semiconductor physics.

A square loop of side 30 cm rotates at 12 rad/s in a 0.1 T field. What is the maximum emf induced?

Given: A square loop of side 30 cm rotates at 12 rad/s in a 0.1 T field. What is the maximum emf induced? These values define the system as per NCERT data. Formula: A = (0.3)² = 0.09 m². This is the standard NCERT relation for this phenomenon. Substitution & Calculation: varepsilon_0 = N B A omega = 1 × 0.1 × 0.09 × 12 = 0.108 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.

The de Broglie wavelength of a particle with momentum 4.0 × 10⁻²⁴ kg m/s is:

Given: The de Broglie wavelength of a particle with momentum 4.0 × 10⁻²⁴ kg m/s is: These values define the system as per NCERT data. Formula: lambda = h/p = frac6.63 × 10⁻³⁴⁴.0 × 10⁻²⁴= 1.6575 × 10⁻¹⁰ m = 0.16575 nm .. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Substituting values like 1.2 × 10⁻⁵, 236 J kg⁻¹ K⁻¹, CH₃CH₂NH₂ etc. into the formula and simplifying step by step. 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 block of mass 1 kg oscillates with a spring of k = 100 N/m . If the amplitude is 10 cm, what is the total energy?

Given: A block of mass 1 kg oscillates with a spring of k = 100 N/m . If the amplitude is 10 cm, what is the total energy? 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: A = 0.1 m, k = 100 N/m . E = 1/2 × 100 × (0.1)² = 0.5 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: Laws of Motion, Work Energy Power, Gravitation and System of Particles, Topic: Newton's laws, work-energy theorem and rotational dynamics.

A solenoid with 1000 turns per meter and current 2 A has a core with relative permeability μ_r = 200 . What is the magn

Given: A solenoid with 1000 turns per meter and current 2 A has a core with relative permeability μ_r = 200 . What is the magnetic field B inside? These values define the system as per NCERT data. Formula: Magnetic field B = μ_0 μ_r H, where H = n I. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Given: n = 1000 m^{-1, I = 2 A, μ_r = 200, μ_0 = 4π × 10⁻⁷ T m A^{-1 . First, H = 1000 × 2 = 2000 A m^{-1 . Then, B = 4π × 10⁻⁷ × 200 × 2000 = 0.5024 T approx 0.5 T . 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 particle in SHM has an amplitude of 6 cm and a frequency of 1.5 Hz . What is its maximum speed? (Take π = 3.14 )

Given: A particle in SHM has an amplitude of 6 cm and a frequency of 1.5 Hz . What is its maximum speed? (Take π = 3.14 ) These values define the system as per NCERT data. Formula: Maximum speed: v_{max = A omega. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: omega = 2π v = 2 × 3.14 × 1.5 = 9.42 rad/s . A = 0.06 m . v_{max = 0.06 × 9.42 approx 0.565 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: Oscillations and Waves, Topic: SHM, wave motion and superposition.

Two lls in parallel have emf 9 V and 3 V with internal resistances 3 Ω and 1 Ω . What is the equivalent internal resis

Given: Two lls in parallel have emf 9 V and 3 V with internal resistances 3 Ω and 1 Ω . What is the equivalent internal resistance? These values define the system as per NCERT data. Formula: For parallel: frac1r_{eq = 1/r_1 + 1/r_2 = 1/3 + 1/1 = 1 + 3/3 = 4/3. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: r_{eq = 3/4 = 0.75 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: Current Electricity, Topic: Resistivity, temperature dependence and circuit analysis.

A pipe open at both ends has a third harmonic frequency of 600 Hz and a wave speed of 400 m/s. What is its length?

Given: A pipe open at both ends has a third harmonic frequency of 600 Hz and a wave speed of 400 m/s. What is its length? These values define the system as per NCERT data. Formula: v_n = n v/2L, n = 3. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: 600 = 3 × 400/2L Rightarrow 600 = 1200/2L Rightarrow 2L = 2 Rightarrow L = 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: Oscillations and Waves, Topic: SHM, wave motion and superposition.

A bar magnet with original m = 1.8 A m² is cut transversely into two equal parts. What is m of each part?

Given: A bar magnet with original m = 1.8 A m² is cut transversely into two equal parts. What is m of each part? These values define the system as per NCERT data. Formula: Given: m = 1.8 A m². This is the standard NCERT relation for this phenomenon. Substitution & Calculation: When cut transversely, each part has half the original magnetic moment. . Each part: m' = 1.8/2 = 0.9 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.

In a new system, the unit of mass is 0.1 kg, length is 2 m, and time is 0.5 s . What is the value of 1 N ( kg m s^{-2 )

Given: In a new system, the unit of mass is 0.1 kg, length is 2 m, and time is 0.5 s . What is the value of 1 N ( kg m s^{-2 ) in this system? These values define the system as per NCERT data. Formula: 1 N = 1 kg m s^{-2. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: New units: kg = 0.1 α, m = 2 β, s = 0.5 γ . 1 N = (0.1 α) (2 β) (0.5 γ)^{-2 = 0.1 × 2 × 4 = 0.8 α β γ^{-2 . 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 brass wire of length 2.2 m and cross-sectional area 2 × 10⁻⁶ m² is stretched by a force of 220 N . If the Young'

Given: A brass wire of length 2.2 m and cross-sectional area 2 × 10⁻⁶ m² is stretched by a force of 220 N . If the Young's modulus of brass is 9 × 10¹⁰ N/m², what is the stress? These values define the system as per NCERT data. Formula: Stress: Stress = F/A = frac2202 × 10⁻⁶= 1.1 × 10⁸ N/m² .. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Substituting values like 1.2 × 10⁻⁵, 236 J kg⁻¹ K⁻¹, CH₃CH₂NH₂ etc. into the formula and simplifying step by step. 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 combination of two lenses in contact has a convex lens ( f = 40 cm ) and a concave lens ( f = 40 cm ). What is the pow

Given: A combination of two lenses in contact has a convex lens ( f = 40 cm ) and a concave lens ( f = 40 cm ). What is the power of the combination? These values define the system as per NCERT data. Formula: f_1 = 40 cm = 0.4 m, f_2 = -40 cm = -0.4 m. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Power: P = P_1 + P_2 = 1/f_1 + 1/f_2 . P_1 = 1/0.4 = 2.5 D, P_2 = 1/-0.4 = -2.5 D . P = 2.5 + (-2.5) = 0 D . 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: Ray Optics and Optical Instruments and Wave Optics, Topic: Refraction, lenses and interference/diffraction.