Of the planets with atmospheres, which is the warmest?
a. Venus
b. Earth
c. Mars
d. Jupiter
[Ques. 2] Four point charges are on the rim of a circle of radius 10 cm. The charges are (in C) +0.50, +1.5, 1.0, 0.50 . If the electrical potential at the circle's center due to the +0.5 charge alone is 4.5 104 V, what is the total potential at the center due to the four charges combined?
a. 18 104 V
b. 4.5 104 V
c. zero
d. 4.5 104 V
[Ques. 3] In a greenhouse, electromagnetic energy in the form of visible light enters the glass panes and is absorbed and then reradiated. What happens to this reradiated electromagnetic radiation from within the greenhouse?
a. 100 returns to the atmosphere.
b. It's partially blocked by glass.
c. It's transformed into ultraviolet upon striking the glass.
d. It's reflected as visible light upon striking the glass.
[Ques. 4] Two equal positive charges are separated by d. Then one of the charges is replaced by a negative charge of the same magnitude. Take the potential at infinity to be zero. In which situation is the potential higher midway between the charges; is this value of potential zero?
a. the first situation; yes
b. the first situation; no
c. the second situation; yes
d. the second situation; no
[Ques. 5] A cube of material with emissivity of 0.4 is heated from room temperature of 20C to 100C. The net power radiated by the cube is 20 W. What is the volume of the cube? ( = 5.6696 108 W/m2K4
a. 0.0014 m3
b. 0.012 m3
c. 0.11 m3
d. 1.8 m3
[Ques. 6] An electron and a proton are each released from rest in the same uniform electric field. The electron moves a distance delectron and the proton moves a distance dproton as each particle's kinetic energy increases by 1.6 eV. How do delectron and dproton compare?
a. delectron < dproton
b. delectron > dproton
c. delectron = dproton
d. The answer depends on the direction of the electric field.
[Ques. 7] The Sun is a slightly variable star. What if the surface temperature of the Sun were to increase from 6 000 K to 6 100 K, what would be the increase in total power radiated assuming no other changes such as radius or emissivity?
a. 1.6 b. 6.8
c. 3.4 d. 14
[Ques. 8] A proton is released from rest in a uniform electric field. Which statement is correct?
a. The proton will move in the same direction as the electric field to regions of higher electric potential.
b. The proton will move in the same direction as the electric field to regions of lower electric potential.
c. The proton will move in the opposite direction as the electric field to regions of higher electric potential.
d. The proton will move in the opposite direction as the electric field to regions of lower electric potential.
[Ques. 9] If the surface temperature of the Earth is 290 K and that of the Sun is 6 000 K, assuming the same emissivities, what is the ratio of the energy radiated per square meter of the Earth to that of the Sun?
a. 0.48 b. 2.3 103
c. 6.4 105 d. 5.5 106
[Ques. 10] A positively charged particle is released from rest in a uniform electric field. Which statement regarding the electron is correct?
a. The particle's kinetic energy increases.
b. The particle's total energy increases.
c. The electric potential at the particle's location increases.
d. The particle's associated electric potential energy increases.
e. None of the statements are correct.
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