A point source is to be used with a concave mirror to produce a beam of parallel light.The source should be placed:
As close to the mirror as possible
At the center of curvature
Midway between the center of curvature and the focal point
Midway between the center of curvature and the mirror
Midway between the focal point and the mirror
Light from a small region of an ordinary incandescent bulb is passed through a yellow filter and then serves as the source for a Young’s double-slit experiment. Which of the following changes would cause the interference pattern to be more closely spaced?
Use slits that are closer together
Use a light source of lower intensity
Use a light source of higher intensity
Use a blue filter instead of a yellow filter
Move the light source further away from the slits
In an experiment to measure the wavelength of light using a double slit, it is found that the fringes are too close together to easily count them.To spread out the fringe pattern,one could:
Decrease the slit separation
Increase the slit separation
Increase the width of each slit
Decrease the width of each slit
None of these
If two light waves are coherent:
Their amplitudes are the same
Their frequencies are the same
Their wavelengths are the same
Their phase difference is constant
The difference in their frequencies is constant
The magnitude of the momentum of a particle can never exceed:
mc, where m is its mass
E/c, where E is its total energy
K/c, where K is its kinetic energy
None of the above, but there is an upper limit
None of the above; there is no upper limit
The units of the Planck constant h are those of:
Energy
Power
Momentum
Angular momentum
Frequency
The quantization of energy, E = nhf, is not important for an ordinary pendulum because:
The formula applies only to mass-spring oscillators
The allowed energy levels are too closely spaced
The allowed energy levels are too widely spaced
The formula applies only to atoms
The value of h for a pendulum is too large
The wavelength of light beam B is twice the wavelength of light beam B. The energy of a photon in beam A is:
Half the energy of a photon in beam B
One-fourth the energy of a photon in beam B
Equal to the energy of a photon in beam B
Twice the energy of a photon in beam B
Four times the energy of a photon in beam B
Which of the following electromagnetic radiations has photons with the greatest energy?
Blue light
Yellow light
X rays
Radio waves
Microwaves
Which of the following electromagnetic radiations has photons with the greatest momentum:
In a photoelectric effect experiment no electrons are ejected if the frequency of the incident light is less than A/h, where h is the Planck constant and A is:
The maximum energy needed to eject the least energetic electron
The minimum energy needed to eject the least energetic electron
The maximum energy needed to eject the most energetic electron
The minimum energy needed to eject the most energetic electron
The intensity of the incident light
The probability that a particle is in a given small region of space is proportional to:
Its energy
Its momentum
The frequency of its wave function
The wavelength of its wave function
The square of the magnitude of its wave function
Maxwell’s equations are to electric and magnetic fields as equation is to the wave function for a particle:
Einstein’s
Fermi’s
Newton’s
Schr.odinger’s
Bohr’s
The energy of a particle in a one-dimensional trap with zero potential energy in the interior and infinite potential energy at the walls is proportional to (n = quantum number:
N
1/n
1/n^2
√n
A particle is trapped in a one-dimensional well with infinite potential energy at the walls Three possible pairs of energy levels are 1) n = 3 and n = 1 2) n = 3 and n = 2 3) n = 4 and n = 3 Order these pairs according to the difference in energy, least to greatest
1, 2, 3
3, 2, 1
2, 3, 1
1, 3, 2
3, 1, 2
The ground state energy of an electron in a one-dimensional trap with zero potential energy in the interior and infinite potential energy at the walls:
Is zero
Decreases with temperature
Increases with temperature
Is independent of temperature
Oscillates with time
The ionization energy of an atom in its ground state is:
The energy required to remove the least energetic electron
The energy required to remove the most energetic electron
The energy difference between the most energetic electron and the least energetic electron
The same as the energy of a Kα-photon
The same as the excitation energy of the most energetic electron
In a laser:
Excited atoms are stimulated to emit photons by radiation external to the laser
The transitions for laser emission are directly to the ground state
The states which give rise to laser emission are usually very unstable states that decay rapidly
The state in which an atom is initially excited is never between two states that are involved in a stimulated emission
A minimum of two energy levels are required
The relation between the disintegration constant λ and the half-life T of a radioactive substance is:
λ = 2T
λ = 1/T
λ = 2/T
λT = ln2
λT = ln(1/2)
In a nuclear reactor the fissionable fuel is formed into pellets rather than finely ground and the pellets are mixed with the moderator This reduces the probability of
Non-fissioning absorption of neutrons
Loss of neutrons through the reactor container
Absorption of two neutrons by single fissionable nucleus
Loss of neutrons in the control rods
None of the above
In a subcritical nuclear reactor:
The number of fission events per unit time decreases with time
The number of fission events per unit time increases with time
Each fission event produces fewer neutrons than when the reactor is critical
Each fission event produces more neutrons than when the reactor is critical
In the normal operation of a nuclear reactor:
Control rods are adjusted so the reactor is subcritical
Control rods are adjusted so the reactor is critical
The moderating fluid is drained
The moderating fluid is continually recycled
Max Plank found his constant h
To get same result as Rayleigh and Jeans
To describe experimental intensity distribution of blackbody at ultraviolet region
To describe Compton scattering
To describe experimental intensity distribution of blackbody at long wavelengths
To describe experimental intensity distribution of blackbody at all wavelengths
Energy and momentum of photon is respectively:
ħω; 1/λ
ħω; 2πħ/λ
m0c^2; 2π/λ
m0c^2; 2πħ/λ
ħω; m0c^2
Nucleus of which element has no neutron:
Deuterium
Tritium
All nucleus for all elements
Hydrogen
Helium
The number of electron states in a shell with principal quantum number n = 3 is:
3
15
18
19
25
The activity of radioactive substance is
–dN/dt
dN/dt
N0
Ndt
A hydrogen atom is in its ground state. Incident on the atom is a photon having an energy of 10.5 eV. What is the result?
The atom is excited to a higher allowed state
The atom is ionized
The photon passes by the atom without interaction
A hydrogen atom makes a transition from the n = 3 level to n = 2 level. It then makes a transition from the n = 2 level to the n = 1 level. Which transition results in emission of the longest-wavelength photon?
The first transition
The second transition
Either transition because the wavelengths are the same for both
A section of hollow pipe and a solid cylinder have the same radius, mass, and length. They both rotate about their long central axes with the same angular speed. Which object has the higher rotational kinetic energy?
The hollow pipe
The solid cylinder
They have the same rotational kinetic energy
Impossible to determine
Two spheres roll down an incline, starting from rest. Sphere A has the same mass and radius as sphere B, but sphere A is solid while sphere B is hollow. Which arrives at the bottom first?
Sphere A
Sphere B
Both arrive
At the same time
Two solid spheres roll down an incline, starting from rest. Sphere A has twice the mass and twice the radius of sphere B. Which arrives at the bottom first?
Both arrive at the same time
Which of the following statements is not true regarding a mass- spring system that moves with simple harmonic motion in absence of friction?
The total energy of the system remains constant
The energy of the system is continually transformed between kinetic and potential energy
The total energy of the system is proportional to the square of the amplitude
The potential energy stored in the system is greatest when the mass passes through the equilibrium position.
For an object undergoing simple harmonic motion,
The amplitudes are usually regarded as being large
The acceleration is greatest when the displacement is greatest
The acceleration is greatest when the speed is greatest
The maximum potential energy is larger than the maximum kinetic energy
The displacement is greatest when the speed is greatest
A skater can spin faster by pulling in her arms closer to her body or spin slower by spreading her arms out from her body. This is due to
Conservation of momentum
Conservation of energy
Newton’s third law
Conservation of angular momentum
The moment of inertia of a body depends on
The angular velocity
The angular acceleration
The mass distribution
The torque acting on the body
The moment of inertia of a wheel about its axle does not depend upon its:
Diameter
Mass
Distribution of mass
Speed of rotation
A mechanical wave generally does NOT
Move the medium from one place to another
Move through a medium
Move through solids
Disturb the medium
A woman sits on a spinning stool with her arms folded. When she extends her arms, which of the following occurs
She increases her moment of inertia, thus increasing her angular speed
She increases her moment of inertia, thus decreasing her angular speed.
She decreases her moment of inertia, thus increasing her angular speed
She decreases her moment of inertia, thus decreasing her angular speed
Her angular speed remains constant by conservation of angular momentum
In elastic collision between the two bodies __________.
Only momentum of the system is conserved
Only the kinetic Energy of the system is conserved
Both the kinetic Energy and Momentum of the system remain the same
Total energy is not conserved
