PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions

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.

With the help of circuit diagram explain the working principle of a transistor amplifier as an oscillator.

Draw a ray diagram to show the working of a compound microscope. Deduce an expression for the total magnification when the final image is formed at the near point.

In a compound microscope, an object is placed at a distance of 1.5 cm from the objective of focal length 1.25 cm. If the eye piece has a focal length of 5 cm and the final image is formed at the near point, estimate the magnifying power of the microscope.

A cell of emf ‘E’ and internal resistance ‘r’ is connected across a variable resistor ‘R’. Plot a graph showing the variation of terminal potential ‘V’ with resistance R. Predict from the graph the condition under which ‘V’ becomes equal to ‘E’.

By what percentage will the transmission ranges of TV tower be affected when the height of the tower is increased by 21%?

Why are high frequency carrier waves used for transmission?

Derive the expression for force per unit length between two long straight parallel current carrying conductors. Hence define one ampere.

Draw the labelled ray diagram for the formation of image by a compound microscope.

Derive the expression for the total magnification of a compound microscope. Explain why both the objective and the eyepiece of a compound microscope must have short focal lengths.

An object is placed at a distance u from a simple microscope of focal length f. The angular magnification obtained depends

A man is looking at a small object placed at his near point. Without altering the position of his eye or the object, he puts a simple microscope of magnifying power 5 X before his eyes. The angular magnification achieved is

In which of the following the final image is erect?
(a) Simple microscope
(b) Compound microscope
(c) Astronomical telescope
(d) Galilean telescope

The focal length of the objective of a compound microscope if f_o and its distance from the eyepiece is L. The object is placed at a distance u from the objective. For proper working of the instrument,
(a) L < u
(b) L > u
(c) f_o < L < 2f_o
(d) L > 2f_o

A compound microscope forms an inverted image of an object. In which of the following cases it it likely to create difficulties? 

An object is to be seen through a simple microscope of focal length 12 cm. Where should the object be placed so as to produce maximum angular magnification? The least distance for clear vision is 25 cm.

A simple microscope is rated 5 X for a normal relaxed eye. What will be its magnifying power for a relaxed farsighted eye whose near point is 40 cm?

Consider the following two statements :-

(A) Line spectra contain information about atoms.

(B) Band spectra contain information about molecules.

Can the image formed by a simple microscope be projected on a screen without using any additional lens or mirror?

A simple microscope using a single lens often shows coloured image of a white source. Why?

The magnifying power of a converging lens used as a simple microscope is `(1+D/f).` A compound microscope is a combination of two such converging lenses. Why don't we have magnifying power `(1+D/f_0)(1+D/f_0)`?In other words, why can the objective not be treated as a simple microscope but the eyepiece can?