Question

True or False

a. The Sun gives off electromagnetic energy only in the visible and ultraviolet regions.

b. When given the same amount of heat a pound of aluminum will undergo a smaller temperature change than iron.

c. An object that is completely submerged in a liquid will be buoyant up by a force equal to its own weight.

d. Temperature and heat are two terms used to describe the same thing.

e. A hollow object will always float in water.

f. A spark from a 4th of July sparkler doesn’t do much damage when it hits your arm because its temperature isn’t very high.

g. Pascal’s principle is demonstrated in the operation of a hydraulic lift used to raise a car in a garage.

h. When an iron rod and an aluminum rod of the same length are heated by the same amount (same change in temperature,) the aluminum rod will have a greater increase in length.

i. When it rains in Seattle, the temperature in the air where the droplets are formed increases (it gets a little warmer.)

j. Black coffee will remain hotter longer than plain water at the same initial temperature.

k. Since atmospheric pressure is about 14.7 lb/in2, there is roughly 14.7 lb of force acting on your body due to the air pressing on you.

l. When a chunk of ice melts into a puddle of water, the particles in the puddle will have a greater amount of translational kinetic energy on the average than those in the ice.

m. It takes less energy to vaporize one gram of water than to melt one gram of ice.

n. The water at the bottom of Lake Eerie is 4 oC.

o. Assuming similar sunny conditions and the lack of facial protection, it is easier to get sunburn on your face when skiing on snow than hiking on a grassy hill.

Answer 1

Answer:

(a) The Sun gives off electromagnetic energy only in the visible and ultraviolet regions.

False.

Solar radiation consisits of large part of EM spectrum and they are ultraviolet, visible, infrared, micro waves, radio waves, X-rays and gamma rays.

(b) When given the same amount of heat a pound of aluminum will undergo a smaller temperature change than iron.

False.

Because it depends on the value of the specific heat of that particular metal. Tha amount of heat required to raise the temperature by 1 ⁰C of i gram material is called specific heat. For aluminium, its specific heat is 0.91kJ/kg.K and for Iron, it is 0.45 kJ/kg.K. Hence, 0.45 kJ heat is enough for 1 kg iron to raise its temperature by 1 K but 0.91 kJ is necessary for aluminium.

(c) An object that is completely submerged in a liquid will be buoyant up by a force equal to its own weight.

True.

According to Archimedes's principle it is correct.

(d) Temperature and heat are two terms used to describe the same thing.

False.

Heat describes the transfer of heat energy between the molecules in the materials and it is measured in joule (J) and Temerature describes the average kinetic energy of the molecules in the material and it is measured by Kelvin (K) or degree centigrade (⁰C)