Electron

Q.

Explain the working of Ruby Laser with the help of an energy level diagram.

Q.

What is the speed of electricity in km/s and m/s

Q.

What are the waves associated with moving protons, electrons, neutrons, atoms known as?

Q.

Which of the following is not the main characteristic of laser beam?

1. Highly intense

2. Highly directional

3. Highly monochromatic

4. incoherent

Q. What is current do it really exists why does it flow opposite to the flow of electron and also why from positive terminal to negative terminal does current really flow or is all thing done by electron

Q.

Give the symbol, relative charge and mass of the three sub atomic particles.

Q.

How does light act like a particle?

Q.

In a ruby laser, the stimulated emission is due to the transition from:

1. Metastable state to any lower state

2. Any higher state to lower state

3. Metastable state to ground state

4. Any higher state to ground state

Q.

Can you Sum up Electric Fields?

Q.

How do you measure effective mass?

Q.

Two conductors A and B are joined by a copper wire. If A is positively charged and B is uncharged, in which direction will the electrons flow?

1. None of the above

2. A to B

3. B to A

4. No transfer of electrons

Q.

What is regarded as universal particle? Proton or Electron?

Q. In a Xerox machine, the black ink's toner particles are negatively charged. They strongly stick to the white A4 sheet paper and form letters and images. What charge could the A4 sheet possess for this process to happen?

1. Positive
2. Negative
3. Neutral
4. None of the above.

Q.

When an atom losses electron, it acquires a net ______ charge.

Q.

In a xerox machine, the black ink's toner particles are negatively charged. They strongly stick to the white A4 sheet paper and form letters and images. What charge should the A4 sheet possess for this process to happen?

1. Positive

2. Negative

3. Neutral

4. Both (a) and (c)

Q.

A ……….. charged object has a deficiency of electrons whereas a ………….. charged object has excess electrons.

Q. nt nttA:Since , matter cannot be concentrated at a point, therefore point charge is not possible.nt nttR:An electron is a point charge.nt nttnt nttExplain the assertion and reasonnn

Q. Atom is electrically neutral. So, in an atom

1. members of protons = number of neutrons, in the nucleus
2. number of particles = number of Y particles
3. number of electrons = number of protons in the necleus
4. number of electrons = number of neutrons, in the nucleur

Q. An electron and a proton are moving with the same kinetic energy along the same direction. When they pass through a uniform magnetic field perpendicular to the direction of their motion, they describe circular paths of the same radius.

1. True
2. False

Q. The nature of ions knocked out from the hot surfaces is

1. nuclei
2. neutrons
3. electrons
4. protons

Q. The compound gallium arsenide is a commonly used semiconductor, having an energy gap $E_g$ of $1.43eV$. Its crystal structure is like that of silicon, except that half the silicon atoms are replaced
by gallium atoms and half by arsenic atoms. Draw a flattened-out sketch of the gallium arsenide lattice, following the pattern of Fig.What is the net charge of the $\left(a\right)$ gallium and $\left(b\right)$ arsenic ion
core? $\left(c\right)$ How many electrons per bond are there? (Hint: Consult the periodic table in Appendix $G$.)

Q. What is population inversion and optical pumping? Explain.

Q.

why current in an electric circuit moves in the opposite direction of the electrons?

Q. An electron has a speed of 4$\times {10}^5$ m/s accurate to point 0.01% with what fundamental accuracy can we locate the position of the electron

Q. What is meant by population inversion and optical pumping?

Q. Which of the following labellings are correct for the arrows marked on the figure?

1. A: Electric current
2. B: Electron flow
3. A: Electron flow
4. B: Electric current

Q. Optical pumping means transferring electrons:

1. from ground state to metastable state
2. from a state higher than the metastable state to the metastable state
3. from a state lower than the metastable state to a state higher than the metastable state
4. from metastable state to a higher excited state

Q. Give three characteristics of photon.

Q. In an electric field an electron is kept freely. If the electron is replaced by a proton, what will be the relationship between the forces experienced by them?