Which of the following statements is true?
All bodies emit electromagnetic radiation, no matter what their temperature is
Only very warm bodies emit electromagnetic radiation
A body must be above 50°C to emit electromagnetic radiation
What happens to the radiation emitted as a body gets hotter?
The intensity and the peak wavelength both increase
The peak wavelength increases and the intensity decreases
The intensity increases and the peak wavelength decreases
Which of these is true for a hot body, such as a star?
If the star emits more radiation than it absorbs, its temperature will decrease
If the star emits less radiation than it absorbs, its temperature will decrease
If the star emits more radiation than it absorbs, its temperature will remain constant
How does an outdoor swimming pool maintain a constant temperature?
The pool must absorb radiation from the Sun and be cooled by the air
The pool must absorb radiation from the Sun and emit the same amount
The pool reflects the radiation from the Sun so the water stays the same temperature
Which of the following can happen when visible light and infrared radiation are absorbed by the surface of Earth?
The Earth’s surface gets cooler
Some of the infrared is radiated back into space with a lower frequency and a higher wavelength
Greenhouse gases are destroyed by the infrared and visible rays
Which technique is used to detect the presence of submarines and shoals of fish in the sea?
P waves
Sonar
X-rays
Sound waves travel at a speed of 1,500 m/s in water. If the time between sending and receiving a reflected sound signal is 0.10 s then how far below the ship is the object being detected?
150 m
75 m
3000 m
Sound waves travel at 330 m/s in air. A bat sends out an ultrasound signal and receives the echo 0.6 s later. How far away is the prey?
99 m
9 m
550 m
P waves are transverse and S waves are longitudinal, they both travel through liquids
P waves are transverse and can only travel through solids
P waves are longitudinal and S waves are transverse, both P and S waves can travel through solids
How do scientists know that the Earth has a liquid outer core?
P waves cannot travel through the core and are not detected on the other side of the Earth
S waves are not detected on the other side of the Earth as they cannot travel through liquids
P waves are refracted when they travel through materials of different densities in the mantle and outer core