. October 2017

Modern Physics: Photoelectric Effect

Q- A photoelectric-effect experiment finds a stopping potential of 1.9 V when light of 295 nm is used to illuminate the cathode.

(a) What is the work function of the metal used to made cathode? 

(b) What is the stopping potential if the intensity of the light is doubled?


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Standing Waves

Q- A 78 cm long guitar string with a linear density of 1.0 g/m is under 225 N tension. It is plucked and vibrates at its fundamental frequency. What is the wavelength of the sound wave that reaches your ear in a 20°C room?


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Ray Optics: Lenses

Q- Two converging lenses having focal lengths of f1 = 10.0 cm and f2 = 24.0 cm are placed 50 cm apart, as shown in the figure. The final image is to be located between the lenses, at the position indicated.

(a) How far to the left of the first lens should the object be positioned?

(b) What is the…

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