Random Facts

Question 1

Unit of momentum

Answer 1

kgm/s

kilogram meters per second

Question 2

Unit of frequency

Answer 2

Hz

Hertz

Question 3

Speed of sound in air (at ±15°C)

Answer 3

340 m/s

Question 4

Which surface is the best emitter (of thermal radiation/infrared?)

Answer 4

Matt black

Question 5

Best absorber (of infra-red/ thermal radiation)?

Answer 5

Matt black

Question 6

Best reflector (of infra-red/ thermal radiation)?

Answer 6

Shiny silver, followed by white

Question 7

Worst emitter (of infra-red/ thermal radiation)?

Answer 7

Shiny silver

Question 8

How do you increase the sensitivity of a liquid-in-glass thermometer?

Answer 8

Make the tube narrower

Question 9

What is a rarefaction?

Answer 9

The area in longitudinal waves (e.g. sound waves) where the particles are spread out /further apart than normal and so the pressure is lower than normal.

Question 10

What is a compression (in terms of sound waves)?

Answer 10

The area of high pressure due to particles being closer together.

Question 11

Range of frequencies heard by a healthy human ear

Answer 11

20 Hz - 20 kHz

Question 12

Define total internal reflection

Answer 12

When all light in a more dense medium is reflected (back into the medium/no refraction)