1. How is Lateral or Transverse magnification given?
a) m = h1/h2
b) m = h2/h1
c) m = h1*h2
d) m = h2 + h1
Explanation: Lateral or Transverse magnification is “m” = h2/h1.
where, h1 is the length of object and h2 is the length of image. “m” is the lateral or transverse magnification.
It is the ratio of the length of image to the object size, both the lengths are measured perpendicular to the principal axis.
2. Name the bending of light, if the beam of light passes obliquely from one medium to another.
a) Refraction
b) Dispersion
c) Reflection
d) Deviation
Explanation: If the beam of light passes obliquely from one medium to another, then the bending of light is known as refraction. Whereas, reflection means change in direction of light, at an interface, between two different mediums, such that the light returns into the medium from where it had originated. Dispersion is the property by which spreading of light takes place according to its color, as it passes through an object. Deviation is the bending of a beam of light, away from a straight line by an angle called angle of deviation
3. From which part of the lens, the ray of light passes without deviation?
a) Optical centre
b) Focus
c) Centre of curvature
d) Pole
Explanation: Optical centre is the part of the lens, through which the ray of light passes without deviation. Focus is the point from where converging and diverging of beam of light takes place, when a narrow beam of light, parallel to principal axis and close to it, is incident on the surface of mirror.
4. When will the convex lens give a real image?
a) Beyond optical centre
b) Beyond focus
c) Beyond centre of curvature
d) Between focus and curvature
Explanation: When the object is situated beyond Focus, the convex lens will always give a real image. If the object is situated in between Focus and curvature, the image will be beyond 2F and the image will be virtual.
5. In X-ray emission tubes, X-ray is emitted by the acceleration of _____
a) Atoms
b) Protons
c) Electrons
d) Neutrons
Explanation: In X-ray emission tubes, the electrons are accelerated by a very high voltage and then decelerated very fast by introducing a metal plate. In this process, the Kinetic energy of electrons is converted into light energy and, thus, X-ray is emitted.
6. Hot bodies emit a specific type of radiation. What are they called?
a) X-rays
b) Black-body radiation
c) Gamma radiations
d) Visible light
Explanation: The phenomenon of black—body radiations was given by Max Planck. He stated that hot bodies emit radiation over a wide range of wavelengths. An ideal body is the one that emits and absorbs radiation of all frequencies. Such a body called a Black Body and the radiations are called Black body radiations
7. An iron rod is heated. As it gets heated, it changes color. Which of the following colors indicates a very high temperature?
a) Red
b) Orange
c) White
d) Blue
Explanation: As the body gets hotter, the frequency of the emitted radiation keeps on increasing. Blue color has the highest frequency out of red, orange and white. Thus, as the iron rod gets heated first it would become red, then orange, then white and then finally blue.
8. Which of the following may not be conserved in a photon-particle collision?
a) Total Energy
b) Total momentum
c) Number of photons
d) Number of particles
Explanation: In a photon-particle collision, total energy and the total momentum are conserved. However, the number of photons may vary. Some photons may get absorbed or new photons may be created. Thus, the number of photons may not be conserved in a collision
9. When an electron jumps from an excited state to ground state it __________
a) Emits a photon having energy 13.6 eV
b) Absorbs a photon having energy 13.6 eV
c) Emits a photon having energy the same as the energy difference between the two states
d) Absorbs a photon having energy the same as the energy difference between the two states
Explanation: Electron in the ground state is extremely stable. Hence, when an electron is in an excited state it tends to come back to its ground state. In this process, a photon is emitted. The Emitted photon has energy equal to the energy difference between the two energy states
10. Stimulated emission is used for the production of ____________
a) Laser
b) X-rays
c) Gamma rays
d) Infrared rays
Explanation: Stimulated emission is the process in which matter at high energy state is perturbed by a photon having energy equal to the energy difference between the current excited state and a lower state. The matter jumps back to the lower state releasing another photon of the same energy. This process is used for the generation of LASERS.