The after glow from some clock faces is caused by atoms
1) being excited,
2) vibrating at frequencies greater than a million billion times per second,
3) remaining for some time in a state of excitation before de-exciting,
and materials exhibiting this property are called
4) fluorescent.
5) phosphorescent.
6) incandescent.
7) luminescent.
[Ques. 2] A spectrum of colors seen in gasoline on a wet street is primarily a result of
1) interference,
2) polarization,
3) refraction,
4) scattering,
5) diffraction,
where
6) the light reaching the eye is polarized by double reflection.
7) only the higher frequencies of light resonate with the gasoline and H2O molecules.
8) the thin film of gasoline spreads the light out into its component colors.
9) light reflecting from the gasoline surface interferes with light reflecting from the water surface.
[Ques. 3] A 2-m-tall person viewing his full-length image in a plane mirror requires a mirror that is at least
1) any visible size.
2) 2 m tall.
3) 1 m tall.
The size of mirror required
4) depends on how far away from it he stands.
5) does not depend on how far away from it he stands.
[Ques. 4] A device that transforms electrical energy to mechanical energy is
1) a generator,
2) a motor,
3) a transformer,
4) any common magnet,
and a device that transforms mechanical energy into electrical energy is a
5) generator.
6) motor.
7) transformer.
[Ques. 5] Refer to the figure above. Assume the switch in the primary has been closed for a few minutes. Then there is a current in the
1) primary, but not the secondary.
2) secondary, but not the primary.
3) primary and secondary.
4) neither the primary nor the secondary.
When the switch is opened suddenly, current in the primary
5) decreases, while current builds up in the secondary.
6) increases, while current decreases in the secondary.
[Ques. 6] A ray of light is incident on a pane of common window glass at an angle of 35 to the normal. The angle of the reflected ray with respect to the normal is
1) 35
2) 55
3) 90
4) 20
and the refracted ray within the glass may be at an angle of
5) 35.
6) 55.
7) 22.
8) 75.
[Ques. 7] Strictly speaking, if a beam of white light is shone through a piece of very thick glass, the first color to emerge from the other side is
1) white.
2) violet.
3) red.
4) green.
This is because
5) all frequencies travel at c.
6) lower frequencies undergo more refraction in a medium.
7) higher frequencies of light travel at a faster average speed through a medium.
8) higher frequencies of light interact with more molecules in a medium.
[Ques. 8] Refer to the figure above. When the switch is closed in the primary circuit,
1) voltage is established in the primary coil
2) a current is established in the primary coil
3) a magnetic field builds up around the primary coil
4) all of the above
and a voltage is induced in the secondary circuit principally because
5) of the voltage in the primary.
6) of the change of current in the primary.
7) the expanding magnetic field about the primary is sensed by the secondary.
[Ques. 9] Refer to the figure above. Assuming that all transitions between levels are possible, how many spectral lines will this atom exhibit?
1) 1
2) 2
3) 3
4) 4
5) 5
The spectral line of highest frequency will result from an electron transition from n = 3 to
6) n = 2.
7) n = 1.
8) either, if the levels are equidistant.
[Ques. 10] The electrons that make up the current in an electric circuit move by
1) interacting with the electric field established in the circuit.
2) bumping into one another in such as way as to send pulses over long distances.
The drift speed of individual electrons making up the current is
3) very low, about a snail's pace.
4) about the speed of sound.
5) about the speed of light.
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