A 50 millimeter focal length camera lens photographs a 4 meter tall tree at a distance of 20 meters. How tall is the image of the tree?

Q-1: A 50 millimeter focal length camera lens photographs a 4 meter tall tree at a distance of 20 meters. How tall is the image of the tree?

ANSWER: 10 MILLIMETERS

Q-2:What reflecting surface forms a geometrically perfect image of a point source located at infinity (such as that approximated by a star)?

1) Paraboloid
2) Ellipsoid
3) spherical
4) Hyperboloid
ANSWER: 1 -- PARABOLOID

Q-3:The dominant charge carriers in p-type semiconductors are:

1) neutrons
2) electrons
3) protons
4) holes
ANSWER: 4 -- HOLES

Q-4:Imagine that a 20 mile diameter hole is bored along the diameter of the Earth extending from the North Pole to the South Pole, that all air and gases are pumped out of this hole, and that the temperature throughout this hole is maintained at 300 Kelvins. A boy throws a ping pong ball into this hole. The ping pong ball would:

1) fall to the center of the Earth and remain forever suspended there.
2) fall to the opposite side of the Earth's surface and remain forever suspended there.
3) forever oscillate in simple harmonic motion along the hole between the loci of the hole
with the opposite surfaces of the Earth.
4) none of the above.
ANSWER: 3 -- FOREVER OSCILLATE IN SIMPLE HARMONIC MOTION ALONG THE OLE

Q-5: An automobile needs an antenna for its radio to play properly because:

1) the automobile's tires insulate it from the ground.
2) the automobile's body acts as a Faraday cage.
3) when the automobile moves, the velocity of the radio signal appears changed with
respect to when it is at rest.
4) the transmitter also uses an antenna.
ANSWER: 2 -- THE AUTOMOBILE'S BODY ACTS AS A FARADAY CAGE.

Q-6:Name any THREE of the four elements that are ferromagnetic at room temperature (25 degrees Celsius).

ANSWER: IRON (FE); COBALT (CO); NICKEL (NI); GADOLINIUM GD)

Q-7: Estimate the number of atoms comprising a silicon chip that is 0.2 millimeters by 0.2 millimeters by 0.1 millimeters, given that the density of silicon is 2.34 grams per cubic centimeter, the number of atoms in a gram-weight is approximately 6 x 1023 atoms, and the atomic weight of silicon is 28:

ANSWER: 2 x 1017

Q-8:A man picks up a 50 kilogram block and carries it up a flight of stairs 10 meters high. He then carries the block back down the stairs and places the block in its original position. What is the NET work done on the block?

1) 1,000 joules
2) 750 joules
3) 500 joules
4) 0 joules
ANSWER: 4 -- 0 JOULES

Q-9: What is the atomic number of Antimony?

1) 33
2) 51
3) 85
4) 122
ANSWER: 3 -- 51