Nucleus — Physics STD 12 Science — Question

Explain current formed in solid conductors in presence of external electric field.

Two metallic wires P and Q of the same material and same length but different cross-sectional areas A1 and A2 are joined together and then connected to a source of emf. Find the ratio of the drift velocities of free electrons in the wires P and Q, if the wires are connected (i) in series, and (ii) in parallel.

A photographic film is coated with a silver bromide layer. When light fells on this film, silver bromide molecules dissociate end the film records the light there. A minimum of 0.6eV is needed to dissociate a silver bromide molecule. Find the maximum wavelength of light that can be recorded by the film.

When are two objects just resolved? Explain. How can the resolving power of a compound microscope be increased? Use relevant formula to support your answer.

Plot a graph showing the variation of stopping potential with the frequency of incident radiation for two different photosensitive materials having work functions W₁ and W₂ (W₁ > W₂). On what factors does the (i) slope and (ii) intercept of the lines depend?

Define resolving power of a compound microscope. How does the resolving power of a compound microscope change when.

1. refractive index of the medium between the object and objective lens increases?
2. wavelength of the radiation used is increased?

Draw a graph showing the variation of potential energy between a pair of nucleons as a function of their separation. Indicate the regions in which the nuclear force is. (i) attractive, (ii) repulsive.

A railroad car of mass M is at rest on frictionless rails when a man of mass m starts moving on the car towards the engine. If the car recoils with a speed v backward on the rails, with what velocity is the man approaching the engine?