Download App

Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsDual Nature of Radiation and Matter2 Marks
Question
Electrons are emitted from a photosensitive surface when it is illuminated by green light but electron emission does not take place by yellow light. Will the electrons be emitted when the surface is illuminated by (i) red light, and (ii) blue light?
✓

Answer

  1. No.
  2. Yes.
Reason: According to colour sequence VIBGYOR, the frequency of red light photons is less than threshold frequency of photo metal but frequency of blue light photons is more than threshold frequency of photo metal; so (i) electrons will not be emitted by red light and (ii) electrons will be emitted by blue light.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "2 Marks Questions" from Dual Nature of Radiation and Matter→Dual Nature of Radiation and Matter — all question types→Physics STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

What does the red shift in the spectrum of a galaxy indicate?
→
Two magnetic poles, one of which is $10$ times as strong as the other, exert on each other a force equal to $9.604\ mN$ , when placed $10 \ cm$ apart in air. Find the strength of the two poles.
→
What will be the change in specific resistance of copper wire when (i) length is made three times (ii) area of cross-section is made three times (iii) radius is made three times and (iv) temperature is increased?
→
A cylindrical capacitor is constructed using two coaxial cylinders of the same length 10cm and of radii 2mm and 4mm:
  1. Calculate the capacitance.
  2. Another capacitor of the same length is constructed with cylinders of radii 4mm and 8mm. Calculate the capacitance.
→
A person wears glasses of power -2.5D. Is the person farsighted or nearsighted? What is the far point of the person without the glasses?
→
A long straight wire carrying a current of $30 A$ is placed in an external uniform magnetic field of $4.0 \times 10^{-4} T$ parallel to the current. Find the magnitude of the resultant magnetic field at a point $2.0 \ cm$ away from the wire.
→
An ideal gas is taken from an initial state $i$ to a final state $f$ in such a way that the ratio of the pressure to the absolute temperature remains constant. What will be the work done by the gas?
→
Answer the following question:
Ray optics is based on the assumption that light travels in a straight line. Diffraction effects (observed when light propagates through small apertures/slits or around small obstacles) disprove this assumption. Yet the ray optics assumption is so commonly used in understanding location and several other properties of images in optical instruments. What is the justification?
→
The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is $0.4\ \Omega,$ what is the maximum current that can be drawn from the battery?
→
A closed organ pipe can vibrate at a minimum frequency of 500Hz. Find the length of the tube. Speed of sound in air = 340m/s.
→