# In the photoelectric effect, the stopping potential is

1. Directly proportional to the photoelectric current
2. Proportional to the square of the frequency of incident photons
3. Determined completely by the properties of the square of metal on which light shines
4. None of the above

# In hydrogen atom on decreasing the principal quantum number n the value of radius (r) and frequency (f) will

1. decrease
2. increase
3. radius increase and frequency decrease
4. frequency increase and radius decrease

1. 2n + l
2. 2n + 2l
3. 2(2l + 1)
4. 2l + 1

# Which part of a transistor is doped the heaviest to supply charge carries

1. Emitter
2. Base
3. Collector
4. None of these

# Find the expectation value of the position of a particle

1. The wave function of a particle is  Ψ = ax
2. and a  particle is limited to the x-axis between x = 0 and x = 1
3. the wave function of a particle is Ψ = 0 elsewhere
4. find the expectation value <x̂> of the position particle.
1. Zero
2. a/2
3. a2/4
4. a2

# If a nucleus with Z = 80 emits the particles in the following sequence:

1. α, β, β, α, α, α, α, α, β, β, β+, α, β+
2. What is the value of Z of the resulting nucleus
1. 56
2. 66
3. 78
4. 82

# To observe the phenomena of interference we require two sources that emit radiation

1. same frequency
2. different frequency
3. same frequency and have a definite phase relationship
4. nearly same frequency

# The energy of a simple harmonic oscillator can be described quantum-mechanically as

1. En = (n + 1/2)ℏω
2. En = (n + 3/2)ℏω
3. (n + 1/2)ω
4. All of the  above

# The radius of the first orbit of the electron in the hydrogen atom is 0.53 A0. Then the radius of the second orbit is

1. 2.12 A0
2. 4.24 A0
3. 0.193 A0
4. None of the above