1. The colors in thin films of soap bubbles are seen due to interference of light.
2. Light radiation is both of wave and particle nature.
3. When a light ray enters from air into glass, it’s wavelength decreases.
4. An air bubble in water acts as a concave lens.
5. Steel is used for making permanent magnets.
6. Lenz’s law is based on energy conservation.
7. Transformer is used for stepping up or stepping down the a.c voltage.
8. Thorium is used as a fuel in the fast breeder reactor of kalpakkam.
9. Polonium was discovered by Madam Marie Curie. She named the newly discovered element
Polonium in honour of her native land Poland.
10. Discovery/Invention
(i) Transistor W. Shockley (1958
(ii) Typewriter Sholz (1868)
(iii) Air Conditioner Wills Heavyland Carrier
(iv) Dynamo Hypolite Pixie (1832)
(v) Microphone Berline (1877)
11. Cadmium being a good absorber of neutrons is used as a controller in nuclear reactor.
12. The ‘Apsara’ reactor in India is called the swimming pool reactor’ because in it heavy water is
used as a moderator.
13. Cobalt 60 is generally used in radiation therapy because it emits gamma rays.
14. Infinite images of an object are formed that is placed between two parallel mirrors.
15. Velocity of light, amplitude and wavelength changes in refraction of light but frequency
remains unchanged.
2. Light radiation is both of wave and particle nature.
3. When a light ray enters from air into glass, it’s wavelength decreases.
4. An air bubble in water acts as a concave lens.
5. Steel is used for making permanent magnets.
6. Lenz’s law is based on energy conservation.
7. Transformer is used for stepping up or stepping down the a.c voltage.
8. Thorium is used as a fuel in the fast breeder reactor of kalpakkam.
9. Polonium was discovered by Madam Marie Curie. She named the newly discovered element
Polonium in honour of her native land Poland.
10. Discovery/Invention
(i) Transistor W. Shockley (1958
(ii) Typewriter Sholz (1868)
(iii) Air Conditioner Wills Heavyland Carrier
(iv) Dynamo Hypolite Pixie (1832)
(v) Microphone Berline (1877)
11. Cadmium being a good absorber of neutrons is used as a controller in nuclear reactor.
12. The ‘Apsara’ reactor in India is called the swimming pool reactor’ because in it heavy water is
used as a moderator.
13. Cobalt 60 is generally used in radiation therapy because it emits gamma rays.
14. Infinite images of an object are formed that is placed between two parallel mirrors.
15. Velocity of light, amplitude and wavelength changes in refraction of light but frequency
remains unchanged.
