Indian School Certificate – ( ISE BOARD )

Recommended Question & Answers for Class 12

1. Find the equation of the plane passing through the intersection of the planes 2x + 2r – 3z – 7 = 0 and 2x + S + 3z – 9 = 0 such that the intercepts made by the resulting plane on the x-axis and the z-axis are equal.

The required plane will be: 2x + 2y – 3z – 7 + k(2x + 5y + 3z -9) = 0 (2 + 2k)x + (2 + 5k)y + (3k – 3)z = 7 + 9k
since x intercept = z intercept
3k – 3 = 2 + 2k
k = 5
and (2 + 10)x + (2 + 25)y + 12z = 52
12x + 27y + 12z = 52

2. Arrange the following electromagnetic waves in increasing order of their frequencies (i.e. begin with the lowest frequency): Visible light, γ rays, X rays, micro waves, radio waves, infrared radiations and ultraviolet radiations. ?

Correct order is: Radio waves. Micro waves, Infra-red radiations, visible light. ultra violet radiations. X-rays and γ rays.

3. What are tranquilizers? Give one example of a tranquilizer.

The chemical substances used for the treatment of stress, mild and severe mental diseases, anxiety and induce sleep are called tranquilizers.

Examples: Equanil, vcronal, valium, etc.