Question

1A) Calculate the velocity of a wave that has a frequency of 4.6 MHz and a wavelength of 650 nm.

a) 2x10⁶ m/s
b) 2.99 m/s

c) 3x10⁸ m/s

d) 4.6x10⁷ m/s

1B) At what temperature is most matter ionized into a plasma?
a) 4500 degrees C
b) 100,000 degrees C
c) 13,000 degrees C
d) 6000 degrees C

1C) A physics instructor is trapped in the arctic (-40 degrees C). He has an inside temperature of 33 degrees C, a surface area of 1.2 m2, and a height of 1.5 m. Find the thermal conduction rate.
a) -73 Watts
b) -32 Watts
c) -53 Watts
d) -49 Watts

1D) Which of the following is a correct statement about convection?
a) Thermal energy is transferred by the movement of a fluid
b) The transfer of thermal energy involves electromagnetic waves
c) Reduction of the transfer of thermal energy is convection
d) Convection is the increasing of the transfer of thermal energy


1E) Which is the correct reason why a steel ship floats?
a) More weight means more buoyant force
b) Steel has a lower density than water
c) Make the volume big enough so it displaces enough water to float
d) Water has a lower density than steel

Answer 1

1A) The velocity of the wave will be

1B) It will be 13000

1C) The thermal conductivity of body is not given hence cant solve.

1D) In convection, actually the fluid moves and carries thermal energy from one place to other.

Thermal energy is transferred by the movement of a fluid

1E) Make the volume big enough so it displaces enough water to float.

The density of steel is higher than that of water and to make it float, it will be made big in volume to acquired large volume so that the liquid displaced is higher.