The top of the troposphere is called the
a. stratopause.
b. tropopause.
c. mesopause.
d. thermopause.
[Ques. 2] A CD player uses a laser whose light frequency is 3.85 1014 Hz. Calculate the energy, in joules, of the photons.
[Ques. 3] Two solenoids are each made of 2 000 turns of copper wire per meter. Solenoid I is 2 m long, while solenoid II is 1 m long. When equal currents are present in the two solenoids, the ratio of the magnetic field BI along the axis of solenoid I to the magnetic field BII along the axis of solenoid II, BI/BII, is
a. 1/4.
b. 1/2.
c. 1.
d. 2
e. 4.
[Ques. 4] The transition between the troposphere and the stratosphere is called the
a. stratopause.
b. tropopause.
c. mesopause.
d. thermopause.
[Ques. 5] Calculate the de Broglie wavelength of a 0.145-kg baseball moving at a speed of 45.2 m/s.
[Ques. 6] A toroid is made of 2 000 turns of wire of radius 2.00 cm formed into a donut shape of inner radius 10.0 cm and outer radius 14.0 cm. When a 30.0-A current is present in the toroid, the magnetic field at a distance of 11.0 cm from the center of the toroid is
a. 0.0857 T.
b. 0.109 T.
c. 0.120 T.
d. 0.600 T.
e. 0.685 T.
[Ques. 7] About 80 of the mass of the atmosphere and most of the clouds and water vapor are located in the
a. stratosphere.
b. troposphere.
c. mesosphere.
d. thermosphere.
[Ques. 8] Calculate the de Broglie wavelength for an electron (m = 1 10-30 kg) moving at 2.4 106 m/s.
[Ques. 9] When a microwave filter consisting of vertical parallel metal rods is in the absorbing position, oscillating currents are set up in the rods. At any one instant, the current in each rod has the same magnitude and direction. At that instant
a. the rods will try to move apart horizontally.
b. the rods will try to move together horizontally.
c. the rods will try to shift vertically upwards.
d. the rods will try to shift vertically downwards.
e. the rods will not be affected because the source of current is not a battery.
[Ques. 10] Exploration of this part of the atmosphere was conducted in the nineteenth century with hot-air balloons.
a. Stratosphere
b. Troposphere
c. Mesosphere
d. Thermosphere
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