Michael is going to the store 6 miles away. He rides his bike at 12 mph for the first half of the trip, then walks at 4 mph for the remainder.
Michael's average speed for the trip to the store is closest to:
1.2 mph
2.4 mph
3.6 mph
4.8 mph
5.10 mph
6.12 mph
7.14 mph
8.exactly halfway between two of the values above
9.impossible to determine
[Ques. 2] Which of the following is not one of the Bohr postulates?
1.The laws of classical physics apply to orbital motion of the electrons but not during transitions from one orbit to another.
2.The possible energies that the electron can have are discrete and depend on the orbit radius.
3.Electrons emit electromagnetic radiation only during transitions between orbits and not while in an allowed orbit.
4.Permissible orbits have an angular momentum which is an integer multiple of h/2.
5.The frequency of the radiation emitted during a transition is related to the energy difference between the orbits by f = E/h.
[Ques. 3] Photons of wavelength scatter elastically from protons at rest. The wavelength of photons scattered at 90 is increased by:
1./137
2.h/2c
3.h/(mec)
4.h/(mpc)
5. cos(45)
6.None of the above
[Ques. 4] An interpretation of the photoelectric effect is that:
1.Light is emitted only when electrons change orbits.
2.Light has a wavelike character.
3.Light is absorbed in quanta of energy E = h
4.Electrons have an associated wave having wavelength = h/p.
5.Photons must have some minimum energy to penetrate a material.
6.More than one of the above
[Ques. 5] A rainbow appears on an oil slick or soap bubble due to:
1.refraction of light.
2.transmission of light.
3.dispersion of light.
4.interference of light.
5.scattering of light.
6.reflection of light.
7.None of the above.
[Ques. 6] An image is formed by a converging lens. Suppose the bottom half of the lens in covered, as shown.
What happens to the image?
1.The image disappears.
2.The image fades.
3.The image rotates.
4.The image moves relative to the lens.
5.The top half of the image disappears.
6.The bottom half of the image disappears.
7.Nothing.
8.None of the above.
[Ques. 7] An object is located on the optical axis and a distance of 8 cm from a thin converging lens having focal length 10 cm. the image of the object is
1.real, upright, and smaller than the object.
2.real, inverted, and smaller than the object.
3.real, inverted, and larger than the object.
4.virtual, upright, and smaller than the object.
5.virtual, inverted, and larger than the object.
6.virtual, upright, and larger than the object.
7.None of the above.
[Ques. 8] Refraction occurs at the interface between two transparent media because:
1.The mass density of the material changes.
2.The frequency of the light changes.
3.The speed of light is different in the two media.
4.The direction of the light changes.
5.Some of the light is reflected.
6.None of the above.
[Ques. 9] The sun appears larger at sunset than it does when overhead because of:
1.Scattering of light.
2.Dispersion.
3.Diffraction.
4.Refraction.
5.An optical illusion.
6.None of the above.
[Ques. 10] The Sun appears to be red as it sets because:
1.Air absorbs red light less than other frequencies (i.e., acts like a red filter).
2.The sunlight has a red-shift when you're moving fastest away from it.
3.The Sun cools down to 5000 K each evening.
4.Light is refracted as it enters the atmosphere.
5.The Sun dies in a glorious fireball each evening and is reborn each morning.
6.None of the above.
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