A plane convex lens is made of glass (n = 1.5) with one flat surface and the other having a radius of 20 cm. What is the focal length (in cm) of the lens?
A. 20
B. 30
C. 40
D. 10
E. 50
Answer: C
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A spaceship with a mass of 20,000 kg is traveling in a straight line at a constant speed of 300 km/s in deep space. Its rockets engines must be: (A) off or (B) firing?
A. off B. firing
Which produces an interference pattern when directed through two suitably spaced slits?
A) light B) sound C) electrons D) all of the above E) none of the above
The heat required to change a substance from the solid to the liquid state is referred to as the
A) heat of fusion. B) heat of vaporization. C) heat of melting. D) heat of freezing. E) heat of condensation.
In a given reversible process, the temperature of an ideal gas is kept constant as the gas is compressed to a smaller volume. Which one of the following statements about the gas is correct?
A) The gas must absorb heat from its surroundings. B) The gas must release heat to its surroundings. C) The pressure of the gas also stays constant. D) The process is adiabatic. E) It is impossible to predict on the basis of this data.