CBSE Guess > Papers > Question Papers > Class X > 2009 > Science > Science

Q. 10. Why does the sky look blue on a clear sunny day? Explain. 2

Ans. See Q.18 (S.A.T), Chapter 11.

Q. 11. State the name and function of the acid produced in our stomach. What remedy would you suggest to a person suffering from indigestion, pain and irritation in the stomach? Name the main ingredient of this remedy and state its function. 3

Ans. Our stomach produces hydrochloric acid. This dilute hydrochloric acid helps in digesting our food without harming the stomach. Sometimes excess acid is produced in the stomach due to various reasons like overeating. The excess acid in the stomach causes indigestion which produces pain and irritation. In order to cure indigestion, antacids are given.
Antacids are a group of mild bases which have no toxic effects on the body. As antacids are basic in nature so they neutralise the excess acid of the stomach and give relief to the person.

The two common antacids used for curing indigestion due to acidity are :
Magnesium hydroxide (milk of magnesia) and Sodium hydrogen carbonate (baking soda).

Q. 12. Draw a circuit diagram to show an electric lamp of resistance 42 and a resistor of 18 connected in series with a battery of 6 V. Calculate
(a) total resistance in the circuit
(b) current flowing through the circuit
(c) potential difference separately across the lamp and the resistor. 3

Ans. (a) Total resistance in the circuit, R = ?
R = R1 + R2 = 42 + 18 = 60      R1 = 42   R2 = 18
b) Current flowing through the circuit, I = ?
Potential difference, V = 6 volts
According to Ohm’s law
V = I R

Science 2009 Question Papers Class X
Delhi		Outside Delhi		Compartment Delhi		Outside Delhi		Foreign
	Set 1 (PDF)		Set 1 (PDF)		Set 1		Set 1		Set 1 (PDF)
					Set 2		Set 2
					Set 3		Set 3