Radio waves are reflected by which of the following ion layers?
a. C
b. D
c. E
d. B
c
You might also like to view...
High mass stars are much less common than low mass stars because they
A) are born in much smaller numbers B) have much shorter lifetimes C) have much longer lifetimes D) two of these
A 0.140-kg baseball is dropped from rest. It has a speed of 1.20 m/s just before it hits the ground. It rebounds with a speed of 1.00 m/s. The ball is in contact with the ground for 0.0140 s
What is the average force exerted by the ground on the ball during that time? A) 2.00 N upwards B) 2.00 N downwards C) 22.0 N upwards D) 22.0 N downwards E) 0 N
A 400-N person stands on the surface of Earth. If he were somehow able to stand on a ladder so that he was twice as far from the center of Earth, he would weigh
1) 0 N. 2) 100 N. 3) 200 N. 4) 400 N. This would be because 5) he would be above the atmosphere. 6) his mass would be the same wherever he was. 7) the force due to gravity obeys the inverse square law.
An electron moves in a region where the magnetic field is uniform and has a magnitude of 80 ?T. The electron follows a helical path which has a pitch of 9.0 mm and a radius of 2.0 mm. What is the speed of this electron as it moves in this region?
a. 48 km/s b. 28 km/s c. 20 km/s d. 35 km/s e. 8.0 km/s