PUC Science 2nd PUC Class 12 - Karnataka Board PUC Important Questions

Name the phenomenon which shows the quantum nature of electromagnetic radiation.

A double convex lens is made of a glass of refractive index 1.55, with both faces of the same radius of curvature. Find the radius of curvature required, if the focal length is 20 cm.

Draw the intensity pattern for single slit diffraction.

Draw the intensity pattern for double slit interference.

State differences between interference and diffraction patterns.

Unpolarised light is passed through a polaroid P₁. When this polarised beam passes through another polaroid P₂ and if the pass axis of P₂ makes angle θ with the pass axis of P₁, then write the expression for the polarised beam passing through P₂. Draw a plot showing the variation of intensity when θ varies from 0 to 2π.

Use Huygens' principle to verify the laws of refraction.

How is linearly polarised light obtained by the process of scattering of light. Find the Brewster angle for air – glass interface, when the refractive index of glass = 1.5. 

How does one explain the emission of electrons from a photosensitive surface with the help of Einstein's photoelectric equation?

Asha's mother read an article in the newspaper about a disaster that took place at Chernobyl. She could not understand much from the articles and asked a few questions from Asha regarding the article. Asha tried to answer her mother's questions based on what she learnt in Class XII Physics.

(a) What was the installation at Chernobyl where the disaster took place? What according to you, was the cause of this disaster?

(b) Explain the process of release of energy in the installation at Chernobyl.

(c) What according to you, were the values displayed by Asha and her mother?

Write the basic nuclear process underlying β⁺ and β^– decays.

The output of an OR gate is connected to both the inputs of a NAND gate Draw the logic circuit of this combinaion of getes and write its truth table.

How is amplitude modulation achieved?

The frequencies of two side bands in an AM wave are 640 kHz and 660 kHz respectively. Find the frequencies of carrier and modulating signal. What is the bandwidth required for amplitude modulation?

List the three stages the annuals and biennial angiosperms have to pass through during their life cycle.

In a flowering plant a microspore mother cell produces four male gametophytes, while a megaspore mother cell forms only one female gametophyte. Explain.

Read the statement and answer the questions that follow.

A flower of brinjal has 520 ovules in its ovary. However, it produces a fruit with only 480 viable seeds.

(a) What could have prevented the rest of the 40 ovules from maturing into viable seeds? Explain giving a reason.

(b) Describe the development of a dicot embryo in a viable seed.

(c) Why certain angiospermic seed albuminous while others are exalbuminous? Explain.

A capsicum flower has 240 ovules in its ovary. But, it produces a fruit with only 180 viable seeds.
 

Arrange the following hormones in sequence of their secretion in a pregnant woman. Mention their source and the function they perform:

hcG, LH, FSH, Relaxin

Where in the fallopian tube does fertilization occur in humans?