Start learning →

AP Intermediate 2nd Year Dual Nature of Radiation and Matter — practice questions

Explore 61 free Dual Nature of Radiation and Matter questions in AP Intermediate 2nd Year Physics. Open each question or exercise to read its content, reference answers and available explanation.

Practise Dual Nature of Radiation and Matter with Quill →

Dual Nature of Radiation and Matter questions and exercises with answers

Showing questions 1–30 of 61.

In a photoelectric experiment, the minimum negative potential applied to the collector plate at which the photocurrent just drops to zero is called theRead the answer and worked solution →The momentum carried by a photon of wavelength $\lambda$ isRead the answer and worked solution →Knock out the photoelectric mythsRead the answer and worked solution →The minimum energy needed to free an electron from a metal is its:Read the answer and worked solution →Work function is usually measured in:Read the answer and worked solution →Photoelectric emission was discovered in 1887 by:Read the answer and worked solution →Below the threshold frequency, photoelectric emission:Read the answer and worked solution →The maximum photoelectric current at high positive voltage is the:Read the answer and worked solution →The negative voltage that just stops the current is called the:Read the answer and worked solution →Photoelectric emission begins after a time lag that is:Read the answer and worked solution →Who explained the photoelectric effect in 1905?Read the answer and worked solution →In Einstein's picture, radiation travels as:Read the answer and worked solution →The number of photoelectrons emitted per second depends on the:Read the answer and worked solution →The kinetic energy of the photoelectrons is set by the:Read the answer and worked solution →Increasing the intensity of light leaves the stopping potential:Read the answer and worked solution →The work function of a surface depends on the:Read the answer and worked solution →Who proposed that matter also has a wave nature?Read the answer and worked solution →The waves associated with moving particles are called:Read the answer and worked solution →The de Broglie relation contains a wave concept together with a:Read the answer and worked solution →Ultraviolet light causing emission was studied in detail by:Read the answer and worked solution →However intense the light, no emission occurs below the:Read the answer and worked solution →Photoelectric current falls to zero at which voltage?Read the answer and worked solution →The de Broglie wavelength of a fast electron is comparable with:Read the answer and worked solution →Match the photoelectric termRead the answer and worked solution →True or false about photoemissionRead the answer and worked solution →Set by intensity or by frequency?Read the answer and worked solution →Order the photoelectric storyRead the answer and worked solution →Complete the photoelectric ruleRead the answer and worked solution →Name the physicistRead the answer and worked solution →Dual nature numbersRead the answer and worked solution →

Worked practice questions

In a photoelectric experiment, the minimum negative potential applied to the collector plate at which the photocurrent just drops to zero is called the

  1. saturation potential
  2. threshold potential
  3. stopping potential
  4. ionisation potential
Show answer and solution

Correct answer: C. stopping potential

1. syllabus defines the relevant potentials. The collector plate $A$ is gradually made more negative with respect to the emitter $C$. 2. As the retarding voltage grows, slower photoelectrons cannot reach $A$, so the photocurrent falls. 3. The minimum retarding potential $V_0$ at which even the MOST energetic photoelectrons are just turned back, and the current becomes zero, is the STOPPING potential. 4. Option A (saturation) is the OPPOSITE limit, the positive potential at which all emitted electrons are collected. Threshold (B) refers to a frequency, not a potential. Ionisation potential (D) is an atomic-physics quantity unrelated to surface photoemission. _Source: syllabus Physics Part 2, Ch 11 "Dual Nature of Radiation and Matter", §11.4.2, p. 4 ¶3._

Open this question →

The momentum carried by a photon of wavelength $\lambda$ is

  1. $h\lambda$
  2. $\dfrac{h}{\lambda}$
  3. $\dfrac{\lambda}{h}$
  4. $h\lambda c$
Show answer and solution

Correct answer: B. $\dfrac{h}{\lambda}$

1. A photon has energy $E = h\nu$ and, since it is massless, $E = pc$ where $c$ is the speed of light. 2. Equate: $pc = h\nu$, so $p = \dfrac{h\nu}{c}$. 3. Using $c = \nu\lambda$ gives $p = \dfrac{h\nu}{\nu\lambda} = \dfrac{h}{\lambda}$. 4. The same expression $p = h/\lambda$ is also what de Broglie applied to MATTER. Option A has wrong dimensions ($h\,\lambda$ would have units of action·length). Option C is the reciprocal. **Option D has an extra factor of $c\lambda$.** _Source: syllabus Physics Part 2, Ch 11, §11.7 "Particle Nature of Light: The Photon" + §11.8 (de Broglie hypothesis), pp. 9–11._

Open this question →

Knock out the photoelectric myths

Read exercise and reference answers
Questions
  1. Question
    Three of these claims about photoelectric emission are false.
    Choices
    1. Explanation
      Extra photons add to the count, never to the energy of one electron.
      Item
      Brighter light raises electron energy.
    2. Item
      A brighter beam ejects more electrons.
      Correct
      Yes
    3. Explanation
      Below the threshold no photon carries enough energy, however many arrive.
      Item
      Bright light works below the threshold.
    4. Explanation
      Ejection is instant, well under a billionth of a second.
      Item
      Emission needs a long build up first.
  2. Question
    Three of these descriptions of the stopping potential are false.
    Choices
    1. Explanation
      That is saturation, the opposite end of the same graph.
      Item
      The voltage that collects every electron.
    2. Explanation
      Threshold names a frequency, not a potential.
      Item
      The frequency below which none escape.
    3. Item
      Retarding voltage that zeroes the current.
      Correct
      Yes
    4. Explanation
      Ionisation is an atomic quantity, not surface emission.
      Item
      The energy that frees a bound electron.
Instructions
Tap away the three false claims in each set about photoelectric emission.
_Source: syllabus Physics Part 2, Ch 11 "Dual Nature of Radiation and Matter", §11.4.2, p. 4 ¶3._

Open this exercise →

How to practise

  1. Choose a Dual Nature of Radiation and Matter question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

Put it into practice

Continue with Dual Nature of Radiation and Matter practice for AP Intermediate 2nd Year. Read explanations as you go. No signup form needed to start.

Practise Dual Nature of Radiation and Matter →

More Physics topics

Current ElectricitySemiconductor ElectronicsSemiconductorsOpticsElectromagnetismAtomsRay and Wave OpticsElectromagnetic Waves