Bihar Board Class 12 (Science) Dual Nature of Radiation and Matter — practice questions
80 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice Bihar Board Class 12 (Science) Dual Nature of Radiation and Matter in the app →In a photoelectric experiment, the minimum negative potential applied to the collector plate at which the photThe momentum carried by a photon of wavelength $\lambda$ isThe minimum energy needed to free an electron from a metal is its:Work function is usually measured in:Photoelectric emission was discovered in 1887 by:Below the threshold frequency, photoelectric emission:The maximum photoelectric current at high positive voltage is the:The negative voltage that just stops the current is called the:Photoelectric emission begins after a time lag that is:Who explained the photoelectric effect in 1905?In Einstein's picture, radiation travels as:The number of photoelectrons emitted per second depends on the:The kinetic energy of the photoelectrons is set by the:Increasing the intensity of light leaves the stopping potential:The work function of a surface depends on the:Who proposed that matter also has a wave nature?The waves associated with moving particles are called:The de Broglie relation contains a wave concept together with a:Ultraviolet light causing emission was studied in detail by:However intense the light, no emission occurs below the:Photoelectric current falls to zero at which voltage?The de Broglie wavelength of a fast electron is comparable with:The work function of a metal depends on the metal's properties and itsElectron emission produced by heating a metal is calledPulling electrons out of a metal with a very strong electric field, as in a spark plug, isField emission needs an electric field of roughly what order?Who discovered photoelectric emission in 1887 during electromagnetic wave experiments?Hallwachs found that an uncharged zinc plate exposed to ultraviolet light becameWhich metal emits photoelectrons even under visible light?Why does a photoelectric tube carry a quartz window?Saturation current flows when the collector receivesThe least retarding potential that reduces photocurrent to zero is theA plot of stopping potential against frequency for one metal isThe slope of the stopping potential versus frequency line equalsCopper shows the photoelectric effect with which light?Above threshold, photoelectric emission begins after a delay of aboutClassical wave theory predicted that maximum photoelectron energy would rise withWhich observation could the wave theory of light NOT explain?Wave theory estimated that, in dim light, an electron would need to absorb energy forIn which year did Einstein propose light quanta to explain photoemission?A metal with a larger work function has a threshold frequency that isPhotons of 5.0 eV hit a metal of work function 2.0 eV. The stopping potential isLight of wavelength 400 nm falls on a metal of work function 2.1 eV. Kmax is aboutA metal's work function is 2.48 eV. Its threshold wavelength is aboutA stopping potential of 1.5 V means the fastest photoelectrons carryA photon of red light has wavelength 600 nm. Its energy is roughlyDoubling the frequency of light on a photosensitive metal makes KmaxTripling the intensity of light at fixed frequency above threshold willMillikan's photoelectric experiments were first aimed atMillikan found Planck's constant from the V0 versus frequency line of which metal?Einstein showed that a light quantum of frequency v carries momentumPhotons pass undeflected through electric and magnetic fields because theyIn vision, which step is best described by treating light as photons?In which year did de Broglie propose that moving matter has wave properties?De Broglie argued for matter waves mainly on the grounds ofIf a particle's speed doubles, its de Broglie wavelength becomesAn electron and a proton move at the same speed. Which has the longer de Broglie wavelength?A proton and an alpha particle have equal kinetic energy. Proton wavelength / alpha wavelength =An electron and a proton have equal momentum. Their de Broglie wavelengths areA 0.15 kg ball moves at 30 m/s. Its de Broglie wavelength is aboutWhy do everyday objects show no wave behaviour?An electron at a few million m/s has a de Broglie wavelength comparable toThe group velocity of a matter wave equals theThe accepted specific charge e/m of the electron is aboutPhotoelectric emission converts light energy intoIn a photocell set-up, light intensity on the emitter is varied by changing theEinstein won the 1921 Nobel Prize in Physics chiefly forWhich experiment showed that electric charge is quantised?One electron volt is equal to how many joules?On what does the work function of a metal depend?Release of electrons from a metal by heating it is called what?Field emission pulls electrons out of a metal using a field of about what size?Which kind of light made the detector sparks stronger in Hertz's experiment?What is the minimum frequency below which a metal emits no photoelectrons called?Zinc, cadmium and magnesium cause photoemission only with which radiation?At fixed frequency and plate potential, how does photocurrent vary with intensity?The energy of emitted photoelectrons depends on which property of the light?A 2.0 mW source emits photons of 3.98 × 10⁻¹⁹ J each. How many per second?What does the de Broglie wavelength of a photon equal?A proton and an alpha particle have equal speeds. What is λ(proton) : λ(alpha)?