Physics Practice MCQ Page 38

Multiple Choice questions for Physics in the sets of 10 each on one page with questions and answers. All sets are useful in the preparation of subject tests for employment or admission.
Question: 3771   Which of the following is established by Brafgg's Method?
  1. X-rays can neither be diffracted nor deflected by electric and magnetic fields
  2. X-rays are not electromagnetic in nature
  3. X-rays are electromagnetic in nature and can be diffracted
  4. X-rays are electromagnetic in nature and can be deflected by electric and magnetic fields.
Question: 3772   which of the following can exist only in integral multiples of h/2π, according to assumption of Bohr's theory?
  1. Principal quantum number
  2. linear
  3. momentum
  4. angular momentum
  5. azumuthal quantum number
Question: 3773   What happens when a high speed electron hits a target?
  1. Heat is produced and simultaneously continuous and characteristic X-rays are emitted
  2. only continuous X-rays are emitted
  3. only characteristic X-rays are emitted and continuous X-rays are not emitted
  4. only heat is produced
Question: 3774   What happens when a high speed electron hits a target?
  1. Heat is produced and simultaneously continuous and characteristic X-rays are emitted
  2. only continuous X-rays are emitted
  3. only characteristic X-rays are emitted and continuous X-rays are not emitted
  4. only heat is produced
Question: 3775   The frequency with which an electron goes around each orbit is given by
  1. f = v/2π
  2. f = 2πV
  3. f= 2πr/v
  4. f= v/2πr
Question: 3776   What is the mass of a photon of energy hv?
  1. hv/c2
  2. hvc2
  3. infinite
  4. indefinite
Question: 3777   In a hydrogen atom, the electron is moving in the xth orbit. The circumference of the orbit (x) and the de-Broglie wavelength of the electrons are related as
  1. x=nh
  2. x=n
  3. x=h/s
  4. x=nh2
Question: 3778   If hydrogen gas is bombarded at room temperature with electrons possessing different energies, the wavelength of radiations first emitted from the gas will correspond to
  1. Lyman series
  2. shortest wavelength of Lymen series
  3. longest wavelength of Lymen series
  4. all series will appear together
Question: 3779   The theory that light is emitted in discrete amounts of energy rather than in a continuous fashion is known as
  1. the photoelectric effect
  2. the quantum theory
  3. Huygen's principle
  4. the electromagnetic theory
Question: 3780   Choose the correct statement
  1. the continuous X-rays are produced because of transition of electrons from outer shell to inner shell whereas the characteristic X-rays are produced by deacceleration of incident electrons
  2. the characteristic as well as the continuous X-rays are produced due to deaccelration of incident electrons.
  3. the continuous X-rays are produced due to deacceleration of incident electrons but the characteristic X-rays are produced due to transition of outer shell electrons to inner shells
  4. the continuous as well as characteristic X-rays are emitted due to transition of electrons from outer to inner shell
Question: 3781   A freshly prepared radioactive source of half life 2 h emits radiation of intensity which is 64 times the permissible safe level. The minimum time after which it would be possible to work safely with this source is
  1. 6 h
  2. 12 h
  3. 24 h
  4. 128 h
Question: 3782   Unstable particles heavier than protons are
  1. leptons
  2. K-mesons
  3. strange particles
  4. hyperons