Science (English Medium) Class 12 - CBSE Question Bank Solutions

Explain, giving reasons, the basic difference in converting a galvanometer into (i) a voltmeter and (ii) an ammeter?

Draw a labelled diagram of a moving coil galvanometer and explain its working. What is the function of radial magnetic field inside the coil?

Draw the circuit for studying the input and output characteristics of and transistor in CE configuration. Show, how, from the output characteristics, the information about the current amplification factor (β_ac) can obtained.

Draw a plot of the transfer characteristics (V₀ versus V_i) for a base-biased transistor in CE configuration. Show for which regions in the plot, the transistor can operate as a switch ?

In the meter bridge experiment, balance point was observed at J with AJ = l.

(i) The values of R and X were doubled and then interchanged. What would be the new position of balance point?

(ii) If the galvanometer and battery are interchanged at the balance position, how will the alance point get affected?

State the principle of the working of a moving coil galvanometer, giving its labeled diagram ?

Outline the necessary steps to convert a galvanometer of resistance RG into an ammeter of a given range ?

State the underlying principle of working of a moving coil galvanometer. Write two reasons why a galvanometer can not be used as such to measure current in a given circuit. Name any two factors on which the current sensitivity of a galvanometer depends.

Three identical capacitors C₁, C₂ and C₃ of capacitance 6 μF each are connected to a 12 V battery as shown.

Find

(i) charge on each capacitor

(ii) equivalent capacitance of the network

(iii) energy stored in the network of capacitors

The muscles of a normal eye are least strained when the eye is focussed on an object

When objects at different distances are seen by the eye, which of the following remain constant?

A person A can clearly see objects between 25 cm and 200 cm. Which of the following may represent the range of clear vision for a person B having muscles stronger than A, but all other parameters of eye identical to that of A?

The focal length of a normal eye-lens is about

The distance of the eye-lens from the retina is x. For a normal eye, the maximum focal length of the eye-lens

A man wearing glasses of focal length +1 m cannot clearly see beyond 1 m

When we see an object, the image formed on the retina is
(a) real
(b) virtual
(c) erect
(d) inverted

Mark the correct options.
(a) If the far point goes ahead, the power of the divergent lens should be reduced.
(b) If the near point goes ahead, the power of the convergent lens should be reduced.
(c) If the far point is 1 m away from the eye, divergent lens should be used.
(d) If the near point is 1 m away from the eye, divergent lens should be used.

A person looks at different trees in an open space with the following details. Arrange the trees in decreasing order of their apparent sizes.

Can virtual image be formed on the retina in a seeing process?

A normal eye has retina 2 cm behind the eye-lens. What is the power of the eye-lens when the eye is (a) fully relaxed, (b) most strained?