Physics Questions and Answers
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
1.0 x 102m2
9. 0 x 102m2
1.0 x 103m2
9.0 x 104m2
Correct answer is A
Generally in thermal/heat conduction, if 1.2 x 106 J is the heat flow per seconds; 30KM-1 is the temperature gradient of the materials; and 400Wm-1K-1 the thermal conductivity of the material, then we have that:
heat flow per seconds per unit area = thermal conductivity x temp. gradient
i.e = 1.2 x 106Area
= 400 x 30
=> 400 x 30 x Area = 1.2 x 106
∴ Area = 1.2 x 106400 x 30
Area = 100m2 or 1.0 x 102m2
6.0 x 104JoC-1
4.0 x 104JoC-1
1.2 x 104JoC-1
8.0 x 104JoC-1
Correct answer is A
2000W heater → 2000J/S
=> Heat supplied by the heater within 10 min
(600 seconds) = 2000 x 600
= 1200000J
∴ Heat capacity MC = 1200000/(30-10)
= 60000J/C
Heat capacity = 6.0 x 104J/C
If the distance from a point source of sound is doubled, by what factor does the intensity decrease?
4.00
2.00
0.50
0.25
Correct answer is A
In general intensity of a wave is the rate of flow of energy across unit area normal to the direction of propagation of the wave intensity α1/r2 where r is the distance away from the point source. Thus if the distance from the point source of the sound wave is doubled, then the intensity will be decreased by a factor of 4