Answer and Explanation:
The main source of earth magnetic field is the metals and iron present in earth crust these metals are mainly found in liquid state in earth crust and we know that whenever there is spinning of these liquid metals then there will magnetic field generate, So the main source of earth magnetic field is the metals present in earth crust.
Object height 10cm is placed in front of plane mirror. The height of the image will also be 10cm as the height of image is same as height of object in the case of plane mirror
<h2>
Time needed is 2545.45 seconds.</h2>
Explanation:
We know equation for power

Here we need to find time when for a 22 kW steam engine to do 5.6 × 10⁷ J of work.
So
Work = 5.6 × 10⁷ J
Power = 22 kW = 22 x 10³ W
Substituting

Time needed is 2545.45 seconds.
C.) A thunderstorm
That’s the Answer