Mathematics 2008 Question Papers

CBSE Guess > Papers > Question Papers > Class X > 2008 >Science > Science Theory

Ans. NQ is the correct emergent ray because NQ ray is parallel to the incident ray (OS) in case of glass slab.

Q. 4. Which of the following two metals will melt at body temperature (37° C)?
Gallium, Magnesium, Caesium, Aluminium.

Ans. Gallium and Caesium will melt at 37°C.

Q. 5. Light enters from air into glass having refractive index 1.50. The speed of light in vacuum is 3.0 × 108 ms–1. What will its speed in glass be?

Sol.

Q. 6. Two solutions A and B have pH values of 5 and 8 respectively. Which solution will be basic in nature?

Ans. The solution B will be basic in nature as its pH value is 8.

Q. 7. Two wires of equal length, one of copper and the other of manganin (an alloy) have the same thickness. Which one can be used for
(i) electrical transmission lines
(ii) electrical heating devices? Why?

Ans. (i) Copper wire can be used for electrical transmission lines because it has a low resistivity and thus it is a good conductor of electricity.
(ii) Manganin can be used for electrical heating devices because it’s resistivity is about 25 times more than that of copper and thus produces a lot of heat on passing current.

Science 2008 Question Papers Class X
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