Specific heat of water Cw = 4.186 × 103?J/(kg · K)
Fundamental charge e =1.60× 10?19 C
Mass of electron me =9.11 × 10?31kg
Mass of proton mp =1.67 × 10?27kg
Planck’s constant h =6.63 × 10?34Js
Coulomb’s constant 1/(4πε0)=8.99 × 109 N · m2 /C2
Boltzmann’s constant k=1.38 × 10?23J/K
A.U. Astronomical Unit = 1.49598 ×1011m: The approx-imate distance from the Sun to the Earth.
Radius of the Earth RE =6.371 × 106m
Linear expansion coefficient of iron αFe = 1.1 ×10?5K?1
Linear expansion coefficient of zinc αZn = 3.0 ×10?5K?1
1 US mile = 1609 meters
1 US gallon = 3.785 liters
Part A: Multiple Choice
1)Incandescent light bulbs are notorious for being relatively inefficient in producing visible light. The tungsten wire inside such a bulb is at a temperature of approximately 3000 K and the emission spectrum is very similar to that of a blackbody. The e?ciency is so low because
Most of the electrons are absorbed in the tungsten wire.
Most of the power is lost due to the resistance of the bulb.
The electric power actually is efficiently transformed into radiation but at 3000 K, most of it is infrared.
A blackbody absorbs more light than it emits,hence it appears black.
2)A solar panel installed on a spaceship has a maximum energy output of 5 kW near the Earth. What is the maximum energy output of the solar panel when the spaceship is near Mars?
(The distance from the Earth to the Sun is 1 A.U. and from Mars to the Sun is 1.5 A.U.)
3.3 kW;
2.2 kW;
1.0 kW;
0.55 kW;
0.20 kW.
3)A scientist measured a 1μA current in an area of a hu-man brain. Unlike current in metals which is carried by free electrons,the current in the brain is mainly car-ried by potassium ions. Each potassium ion has one unit of charge e. This current corresponds to the ?ow of how many potassium ions per second?
6× 105;
6× 106;
6× 108;
6× 1012;
6× 1018 .
4)The gas supply to your physics professor’s house suddenly stops due to a gas line failure. It is winter and the temperature outside is ?5 oC and constant. Assuming all the doors and windows remain closed, which of these graphs best describes how the temperature in the house changes with time after the gas supply stops?
5)The ray of light travelling in air hits the parallel glass plate as shown. Which are the possible continuations of the light ray?