Midterm #2

*Practice Midterm Questions*: - ans 1. You use a concave mirror to focus light from a window 1.8 m away. It makes an image 20 cm in front of the mirror. Assemble a sketch of this problem and label the object distance and image distance. Put the window/object on the left and the mirror on the right. Make sure you choose the correctly shaped mirror. Put the unwanted mirror in the upper right corner. - ans match pictures 2. You use a concave mirror to focus light from a window 1.8 m away. It makes an image 20 cm in front of the mirror. Assign the values in the problem to the correct variables. do = di = - ans do = 1.8m di = 20 cm 3. Choose the equation or equations that you will need to use to find the focal length of the mirror and the image height. a. Snell's law: n1sinθ1 = n2sinθ2 b. B Field at the center of a loop: B = Nµ0L/2R c. Mirror or Thin Lens Equation: 1/do + 1/di =1/f, ho/hi = -do/di d. Force between current carrying wires separated by distance d: F = µ0I1I2L/2πd e. B-field of a long straight wire: B = μ0I/2πR f. Magnetic Flux: Φ = BAcosθ g. Index of refraction n = c/v h. Force on a current carrying wire: F = BILsinθ i. Doppler shift: ƒl = ƒ(1 ± u/c) j. Magnetic Force on a moving charge: F = qvBsinθ k. c = fλ l. Torque on a loop: τ = NIABsinθ m. Force on an object mass m moving in a circle of radius R = mv2/R