1. | \(2.7 \times 10^{-18} ~\text{ms}^{-1}\) |
2. | \(9 \times 10^{-2} ~\text{ms}^{-1}\) |
3. | \(3 \times 10^{-31}~\text{ms}^{-1}\) |
4. | \(2.7 \times 10^{-21} ~\text{ms}^{-1}\) |
An electron with an initial velocity v= is in an electric field E It's de Broglie wavelength at the time is given by:
1.
2.
3.
4.
The ratio of momenta of an electron and an \(\alpha \text-\)particle which are accelerated from rest by a potential difference of \(100~\text{V}\) is:
1. \(1\)
2. \(\sqrt{\frac{2m_e}{m_{\alpha}}}\)
3. \(\sqrt{\frac{m_e}{m_{\alpha}}}\)
4. \(\sqrt{\frac{m_e}{2m_{\alpha}}}\)
The fact that electric charges are integral multiples of the fundamental electronic charge was proved experimentally by
(1) Planck
(2) J.J. Thomson
(3) Einstein
(4) Millikan
A narrow electron beam passes undeviated through an electric field E = and an overlapping magnetic field . If electric field and magnetic field are mutually perpendicular. The speed of the electrons is
1. \(60\) m/s
2.
3.
4.
The specific charge of an electron is
(a) coulomb
(b) stat coulomb
(c) coulomb/kg
(d) coulomb/kg
Cathode rays are similar to visible light rays in that
(1) They both can be deflected by electric and magnetic fields
(2) They both have a definite magnitude of wavelength
(3) They both can ionize a gas through which they pass
(4) They both can expose a photographic plate
A beam of electrons is moving with constant velocity in a region having electric and magnetic fields of strength and 0.5 T at right angles to the direction of motion of the electrons. What is the velocity of the electrons
1. 20 2. 40
3. 8 4. 5.5
Electron volt is a unit of
(1) Potential
(2) Charge
(3) Power
(4) Energy
The ratio of specific charge of an -particle to that of a proton is
(1) 2 : 1
(2) 1 : 1
(3) 1 : 2
(4) 1 : 3