In an a. c generator, coil of N turns and area A is rotated at ω radians per second in a uniform magnetic field B. Deduce an expression for an emf ε induced in it. Assume that the maximum emf is ε0. Plot the variation of induced emf with time.

How is coal extracted from mountaintop removal mines? a. dynamite is used to create underground tunnels where miners go to extract the coal. b. dynamite is used to break apart rocks and then draglines are used to remove the broken rock and reach the coal. c. coal in mountaintops is extracted by digging strips in the landscape to reach the coal. d. placer deposits in mountain river bottoms are removed by