Question

B. A wave on a long string is represented by the equation y = 1.0 m sin[(0.5 m−1) x + (1.5 s−1) t]. The speed and the direction of motion of this wave is:

(a) 0.33 m/s in the +x direction. (b) 0.75 m/s in the +x direction. (c) 3.00 m/s in the +x direction. (d) 0.33 m/s in the −x direction. (e) 3.00 m/s in the −x direction

C. Two cello strings, with the same tension and length, are played simultaneously. Their
fundamental frequencies produce audible beats with a frequency of 8 Hz. The string with the
lower pitch (frequency) is tuned to an “A” (a frequency of 220 Hz). What is the approximate
ratio of the linear mass density μ of the string with the higher pitch to that of the string
with the lower pitch?
(a) 0.93 (b) 0.97 (c) 1.02 (d) 1.04 (e) 1.06
D. What is the approximate minimum diameter of an objective lens required to resolve two
bacteria lying 10−5 m apart on a glass slide placed 10 cm below an objective lens if they are
being illuminated with green light λ = 5.3 × 10−7 m)?
(a) 1 mm (b) 5 mm (c) 20 mm (d) 50 mm (e) 100 mm

Answer 1