Electromagnetic Waves:
Radio waves, television waves, and microwaves.
Answer:
857.5 m
2.8583×10⁻⁶ seconds
Explanation:
Time taken by the sound of the thunder to reach the student = 2.5 s
Speed of sound in air is 343 m/s
Speed of light is 3×10⁸ m/s
Distance travelled by the sound = Time taken by the sound × Speed of sound in air
⇒Distance travelled by the sound = 2.5×343 = 857.5 m
⇒Distance travelled by the sound = 857.5 m
Time taken by light = Distance the light travelled / Speed of light

Time taken by light = 2.8583×10⁻⁶ seconds
Answer: Whenever two objects are touching, they usually exert forces on each other. The force of gravity, on the other hand, is an example of a force that exists between objects without them having to be in contact. Objects with mass exert forces on each other via the force of gravity.
HOPE IT HELPED:) HAVE A NICE DAY
Answer:
Explanation:
a ) wave length of waves in water
= velocity / frequency
= 1482 / (18 x 1000)
= .0823 m
= 8.23 cm
b ) Applying Doppler's effect relation
frequency of reflected wave
= 18000 [ 1482 / (1482 - 4.95 ) ]
= 18000 x 1.003385
= 18061
Difference in frequency= 61 Hz