Wednesday, May 1, 2013

What is the theoretical limit of the efficiency of a single-crystal single-junction cell in a photovoltaic system?


Q-1: What is the theoretical limit of the efficiency of a single-crystal single-junction cell in a photovoltaic system?
1) 9 percent
2) 29 percent
3) 79 percent
4) 99 percent
ANSWER: 2 -- 29 PERCENT
Q-2:  What is the ideal efficiency of a reversible heat engine cyclically operating between a source temperature of 600 degrees Kelvin and a sink temperature of 150 degrees Kelvin?
ANSWER: 75 PERCENT
Q-3:  A four cycle internal combustion automobile engine operates on what kind of cycle?
1) Rankine
2 Otto
3) Brayton
4) Joule
ANSWER: 2 -- OTTO
Q-4:  If materials become superconducting when cooled, any magnetic field will be expelled. This is called:
1) diamagnetism
2) repulsion
3) the Landow Effect
4) the Meissner effect
ANSWER:4 -- THE MEISSNER EFFECT
Q-5:  A kilogram of water goes from 90 degrees Celsius to 10 degrees Celsius in a period of 2 hours. If the specific heat of water is 4 kilojoules per kilogram per degree Celsius, how much heat has the water lost?
ANSWER: 320 KILOJOULES or 320,000 JOULES
Q-6:  What is the total resistance of three 15-ohm resistors connected in parallel?
ANSWER: 5 OHMS
Q-7: A proton and an alpha particle pass through the gap of a strong magnet. If both particles have the same initial velocity, how many times greater will the defection of the proton be relative to the deflection of the alpha particle? Will it be:
1) the same
2) 2 times
3) 4 times
4) 8 times
ANSWER: 2 -- 2 TIMES
Q-8:  Pendulum "A" swings through one complete oscillation in one second. If Pendulum "B" is four times as long as Pendulum "A", how long does it take Pendulum "B" to swing through one complete oscillation?
ANSWER: 2 SECONDS
Q-10: An electric clothes dryer is connected to a 100-volt source. How much current does it use if it requires 2,000 watts of electric power?
ANSWER: 20 AMPERES
Q-11:  The actual mechanical advantage of a block and tackle is 5. The ideal mechanical advantage is 6. How many strands support the mass to be lifted?
ANSWER: 6

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