Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.

ISC Class 12 Physics Solved Question Paper 2006

Short Answer Type

31. Name the essential parts of a spectrometer.

671 Views

32.

(i) Draw a ray diagram to show how the image of a distant object is formed by a refracting astronomical telescope when in normal use.

(ii) State one advantage of a reflecting astronomical telescope over a refracting astronomical telescope.

902 Views

33. The refractive indices of a material for red, violet and yellow colour lights are 1.52. 1.62 and 1.59 respectively. Calculate the dispersive power of the material. If the mean deviation is 40°, what will be the angular dispersion produced by a prism of this material ?

μ_r = 1.52

μ_v = 1.62

μ_y = 1.59

Here δ = (μ_v - 1) A

δ = 40°

Dispersive power,

$space fraction numerator straight delta subscript straight v space minus space straight delta subscript straight r over denominator straight delta end fraction space equals space fraction numerator left parenthesis straight mu subscript straight v space minus space straight mu subscript straight r right parenthesis straight A over denominator straight delta end fraction space space space space space space space space space space space space space space space space space equals space fraction numerator straight mu subscript straight v space minus space straight mu subscript straight r over denominator straight mu subscript straight y space minus space 1 end fraction space space space space space space space space space space space space space space space space space equals space fraction numerator 1.62 space minus space 1.52 space over denominator 1.59 space minus space 1 end fraction space space space space space space space space space space space space space space space space equals space fraction numerator 0.10 over denominator 0.59 end fraction space equals space 10 over 59$

Angular dispersion (δ_v - δ_r) = (μ_v - μ_r) A

= $fraction numerator left parenthesis straight mu subscript straight v space minus space straight mu subscript straight r right parenthesis space straight x space straight delta over denominator left parenthesis straight mu subscript straight y space minus space 1 right parenthesis end fraction space equals space 10 over 59 space x space 40 space equals space 400 over 59$

258 Views

34. What is the cause of spherical aberration in lenses? State a method to minimise this defect.

512 Views

35. In a Cathode ray tube, an electron passes through a field, where the electric field E and the magnetic field B are uniform and mutually perpendicular. Derive an expression for the velocity at which the electron reaches the screen undeflected.

305 Views

36.

(i) What is meant by the term activity of a radioactive substance.

(ii) A radioactive sample has a half life of 1.4 x 10¹⁶ seconds and a mass number of 238. Calculate the number of disintegration/s of 1g of this sample.

350 Views