Of the following objects, which will emit mostly infrared light?
A. a red laser beam
B. a star like our Sun
C. an LED (Light-Emitting Diode)
D. a cup of hot coffee
Answer: D
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An athlete doing push-ups performs 650 kJ of work and loses 425 kJ of heat. What is the change in the internal (thermal) energy of the athlete?
A) -225 kJ B) -1075 kJ C) 1075 kJ D) 225 kJ E) 276 kJ
A loop of radius r = 3.0 cm is placed parallel to the xy-plane in a uniform magnetic field = 0.75 T
The resistance of the loop is 18 ?. Starting at t = 0, the magnitude of the field decreases uniformly to zero in 0.15 seconds. What is the magnitude of the electric current produced in the loop during that time? A) 0.79 mA B) 3.9 mA C) 1.7 mA D) 2.1 mA E) 0.20 mA
A charge per unit length given by ?(x) = bx, where b = 12 nC/m2, is distributed along the x axis from x = +9.0 cm to x = +16 cm. If the electric potential at infinity is taken to be zero, what is the electric potential at the point P on the y axis at y = 12 cm?
a. 5.4 V b. 7.2 V c. 9.0 V d. 9.9 V e. 16 V
The magnitude of the orbital angular momentum L of an electron in a certain atom is equal to 3.464?
Which of the following angles could NOT be the angle between the orbital angular momentum vector of the electron and an arbitrary z-direction? A) 54.7° B) 90.0° C) 107° D) 73.2° E) 0.00°