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#photoelectric effect

44 public questions tagged with this topic.

PHYSICS

Light of wavelength 350 nm is incident on a metal with work function 2.0 eV . What is the stopping potential? (Take h c

Given: Light of wavelength 350 nm is incident on a metal with work function 2.0 eV . What is the stopping potential? (Take h c = 1240 eV nm ) These values define the system as per NCERT data. Formula: E = h c/lambda = 1240/350 approx 3.54 eV. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: K_{max = E - phi_0 = 3.54 - 2.0 = 1.54 eV . V_0 = fracK_{maxe = 1.54 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: Electric Charges and Fields and Electrostatic Potential, Topic: Electric field, potential and capacitance concepts.

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PHYSICS

Light of wavelength 400 nm produces photoelectrons with a stopping potential of 0.8 V from a metal. What is the work fun

Given: Light of wavelength 400 nm produces photoelectrons with a stopping potential of 0.8 V from a metal. What is the work function of the metal in eV? (Take h c = 1240 eV nm ) These values define the system as per NCERT data. Formula: Photon energy E = h c/lambda = 1240/400 = 3.1 eV. This is standard NCERT relation. Substitution & Calculation: K_{max = e V_0 = 0.8 eV . phi_0 = E - K_{max = 3.1 - 0.8 = 2.3 eV . Result: The computed value matches expected outcome and confirms correct choice as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Dual Nature of Radiation and Matter, Topic: Photoelectric effect, stopping potential, Kmax = eV₀, work function and photon energy. The section explains definitions, governing laws, formulas like μ₀ = 4π × 10⁻⁷ T·m/A, units and illustrative examples.

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PHYSICS

The threshold wavelength for a metal is 500 nm . What is the work function of the metal in eV? (Take h = 6.63 × 10⁻³

Given: The threshold wavelength for a metal is 500 nm . What is the work function of the metal in eV? (Take h = 6.63 × 10⁻³⁴ J s, c = 3 × 10⁸ m/s, 1 eV = 1.6 × 10⁻¹⁹ J ) These values define the system as per NCERT data. Formula: Threshold frequency v_0 = c/lambda_0 = frac3 × 10⁸⁵⁰⁰ × 10⁻⁹= 6 × 10¹⁴ Hz. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: phi_0 = h v_0 = 6.63 × 10⁻³⁴ × 6 × 10¹⁴= 3.978 × 10⁻¹⁹ J . phi_0 = frac3.978 × 10⁻¹⁹¹.6 × 10⁻¹⁹ approx 2.49 eV . 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.

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PHYSICS

The threshold wavelength of a metal is 550 nm . What is its work function in joules? (Take h = 6.63 × 10⁻³⁴ J s, c

Given: The threshold wavelength of a metal is 550 nm . What is its work function in joules? (Take h = 6.63 × 10⁻³⁴ J s, c = 3 × 10⁸ m/s ) These values define the system as per NCERT data. Formula: v_0 = c/lambda_0 = frac3 × 10⁸⁵⁵⁰ × 10⁻⁹ approx 5.455 × 10¹⁴ Hz. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: phi_0 = h v_0 = 6.63 × 10⁻³⁴ × 5.455 × 10¹⁴ approx 3.617 × 10⁻¹⁹ 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: Oscillations and Waves, Topic: SHM, wave motion and superposition.

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PHYSICS

What is the primary source of energy for photoelectrons in the photoelectric effect?

In the photoelectric effect, photoelectrons gain energy from incident light photons, which transfer their energy to the electrons. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Physics Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII, continuing as per NCERT advisory for 2026-27),Topic: Fundamental laws, definitions and applications as per latest NCERT. The section explains governing laws, formulas like μ₀ = 4π.

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PHYSICS

What happens to photoelectric emission if the frequency of incident light is below the threshold frequency?

No photoelectric emission occurs if the frequency is below the threshold frequency, as the photon energy ( h v ) is less than the work function ( phi_0 ).

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Dual Nature of Radiation and Matter, Topic: Photoelectric effect, stopping potential, Kmax = eV₀, work function and photon energy. The section explains definitions, governing laws, formulas like μ₀ = 4π × 10⁻⁷ T·m/A, units and illustrative examples.

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PHYSICS

What does the photoelectric effect demonstrate about the nature of light?

The photoelectric effect shows that light behaves as discrete packets of energy (photons), supporting its particle nature. This follows from NCERT principle where relation explains outcome clearly for students.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Dual Nature of Radiation and Matter, Topic: Photoelectric effect, stopping potential, Kmax = eV₀, work function and photon energy. The section explains definitions, governing laws, formulas like μ₀ = 4π × 10⁻⁷ T·m/A, units and illustrative examples.

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PHYSICS

Which process allows electrons to escape from a metal surface when illuminated by light of suitable frequency?

Photoelectric emission occurs when light of sufficient frequency provides energy to overcome the work function, ejecting electrons. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Physics Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII, continuing as per NCERT advisory for 2026-27),Topic: Fundamental laws, definitions and applications as per latest NCERT. The section explains governing laws, formulas like μ₀ = 4π.

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