Answer:
Spinning permanent magnets within an array of fixed permanent magnets.
Explanation:
Any relative motion between magnets (be they permanent or electromagnetic) and a coil of wire will induce an electric current in the coil.
What will not induce an electric current is the relative motion between the two coils of wire (because there is no change in magnetic field), or the relative motion between two magnets (there are no coils of wire to induce the current into).
Therefore, spinning permanent magnets within an array of fixed permanent magnets does not induce an electric current.
<em>In all other choices, coils of wire are there to be induced current into, and magnets are present to create changing magnetic fields. </em>
The answer is C, as the frequency gets higher the wavelength gets shorter
Answer: Gamma Rays
Explanation: Because they are safe yet powerful enough for the spectrum.
Answer:
t = 1.22 s
Explanation:
Given that,
The initial upward velocity component of a football = 12 m/s
The horizontal velocity component is 20 m/s
We need to find the time required for the football to reach the highest point of the trajectory. Let the time is t.
Using first equation of motion to solve it such that,
u is initial velocity
v is final velocity
a = -g
so,
So, the required time taken by the football to reach the highest point is 1.22 seconds.
