Question

7. A convex lens has a focal length of f= 50cm. An object is placed 40cm from the lens.Compute the location of the image.

		-200 cm
		200 cm
		22.2 cm
		-22.2 cm

8. An LED flashlight produces a beam with an intensity of I= 7.36W/m² when it illuminates a circular piece of matte black painted steel having a radius of r = 40cm. If the steel has a mass of m= 5kg, what is the acceleration of the mirror due to the force exerted by the absorbed light?

		2.5x10-9 m/s2
		4.9x10-9 m/s2
		2.5x10-8 m/s2
		2.3x10-7 m/s2

9. What is the relation, if any, between the direction of the electric component and the magnetic component of an electromagnetic wave? Select ALL that apply. May bemore than one correct answer.

		There is no general relationship
		The electric and magnetic components are perpendicular
		|E|=|B|c
		|B|=|E|c

10. Polarized light from a laser with an intensity of I= 1,000W/m² is incident on two polarizers. The first polarizer has its transmission axis aligned with the electric field ofthe incident laser beam. The transmission axis of the second polarizer makes an angle of θ= 30deg with that of the first. Calculate the intensity of the transmitted light from the second polarizer.

		750 W/m2
		430 W/m2
		375 W/m2
		0 W/m2

11. A coil of resistance 15ohm and self-inductance 3mH is connected across an ideal 10V battery. What is the initial current?

		150mA
		150A
		0.67 A
		6.67 mA

12. For the above circuit what is the final current?

		0A
		0.67 A
		6.67 mA
		6.67 A

13. Two flat loops of wire, A and B, lie in the x−y plane. Loop A is centered at the origin and carries a current IA= 20A, which produces a flux φB= 100Wb in coil B. Loop B carries a current IB= 10A, which creates a flux of 50Wb in loop A. Compute the mutual inductance.

		2000 H
		1000 H
		10 H
		5 H

Answer 1