As a result of annihilation of electron and positron, number of γ–ray (Gama ray) photons are: ________?

Related Mcqs:

1. In addition to the daughter nucleus and an electron or positron, the products of a beta decay

   A. Neutrons
   B. Neutrino
   C. Alpha particle
   D. Proton

   Submitted by: Alina Malik

2. When an electron moving with a uniform speed in a vacuum enters a magnetic field in a direction perpendicular to the field the subsequent path of the electron is ___________________?

   A. a straight line parallel to the field
   B. a parabola in a plane perpendicular to the field
   C. a circle in a plane perpendicular to the field
   D. a straight line along its initial direction

3. For confinement of electron in a box of radius 10-14m the electron, speed should be_____________?

   A. 107m/sec
   B. Should be greater than the speed of light.
   C. Be zero
   D. Not be wave-like

4. In bringing an electron towards the second electron, the electrostatic potential energy of the system

   A. Decreases
   B. increases
   C. remains the same
   D. becomes zero

   Submitted by: Tauseef Ali

5. A transmitting station emits radio waves of wavelength λ at power P. If h is Planck’s constant & c the speed of light what is the rate of emission of photons ?

   A. λ
   B. Speed of sound
   C. Speed of lightB.
   D. h

6. In normal state of energy the incident high energy photons will be______________?

   A. Stimulated
   B. Absorbed
   C. Cause X-ray emission
   D. Cause laser production

7. The linear momentum of an X-ray photon of wavelength 0.1A is_______________?

   A. 6.625x1023N-s
   B. 66.25x1023N-s
   C. 662.5x1023N-s
   D. data is insufficient

8. X-ray are________________?

   A. of unknown nature
   B. high energy electrons
   C. high energy photons
   D. radio isotopes

9. In obtaining an X-ray photograph of our hand we use the principle of______________?

   A. photo electric effect
   B. ionization
   C. shadow photograph
   D. any of above

10. In an X-ray tube electrons each of charge e are accelerated through V potential difference allowed to hit a metal target. The wavelength of the X-rays emitted is_______________?

    A. he/ev
    B. he/Vc
    C. eV/h
    D. impossible to predict