<h3><u>Answer;</u></h3>
Velocity and wavelength are directly proportional when frequency is kept constant.
<h3><u>Explanation;</u></h3>
- <em><u>Frequency of a wave is the number of complete oscillations made by a given wave in one second. </u></em>
- <em><u>Wavelength on the other hand, is the distance between two successful crests or troughs in a transverse wave or two successful rarefactions or compressions in a longitudinal waves.</u></em>
- <em><u>The speed of a wave is given by the product of the frequency of a wave and the wavelength.</u></em>
- <em><u>Speed = Frequency × wavelength, </u></em>
- <em><u>Therefore, if frequency is kept constant, then the speed of a wave is directly proportional to the wavelength, such that an increase in wavelength increases the speed of the wave and vice versa.</u></em>
D. A magnetic field created by the electric current causes the compass needle to move.
Answer:
Both A and B
Explanation:
The interaction of magnetic fields and armature results into a rotational force of the armature hence turning motion. It's important to note that you will always need two magnetic fields in order to experience the force since one magnetic field is at the rotating armature and another at the casing. Considering the arguments of these two technicians, both of them are correct in their arguments.
The amount of force required to stretch or compress the spring is known as the spring force. Its unit is Newton(N). Force is needed to stretch spring is 10.2 N.
<h3>What is spring force?</h3>
The force required to extend or compress a spring by some distance scales linearly with respect to that distance is known as the spring force. Its formula is
F = kx
The given data in the problem is;
F is the spring force =?
K is the spring constant= 8.5 N/m
x is the length by which spring got stretched = 1.2m

Hence the force is needed to stretch the spring is 10.2 N.
To learn more about the spring force refer to the link;
brainly.com/question/4291098