Science 2007 CBSE [ All India ] Set I
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Q1
What is the role of a catalyst in a chemical reaction?
Marks:1View AnswerAnswer:
Catalyst helps in increasing the rate of reaction and hence reaction becomes fast.
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Q2
Which class of compounds gives a positive Fehling’s test? Marks:1View AnswerAnswer:
Out of syllabus. -
Q3
Approximately how many stars are there in the Milky Way? out of syllabus Marks:1View AnswerAnswer:
Out of syllabus.
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Q4
What is meant by the statement, “Potential difference between points A and B in an electric field is 1 volt"? Marks:1View AnswerAnswer:
It means that 1 joule of work is needed to bring one coulomb of charge from point A to B in the given electric field. -
Q5
Name the excretory unit of a kidney. Marks:1View AnswerAnswer:
Nephron -
Q6
What are phytohormones? Marks:1View AnswerAnswer:
Out of syllabus -
Q7
Name the organic acid present in vinegar. Write a chemical equation which represents the commercial method for the preparation of this acid from methanol. Marks:2View AnswerAnswer:
Acetic acid is present in vinegar. Rest of the question is out of syllabus. -
Q8
Distinguish between ‘artificial’ and ‘natural’ satellites. Why are artificial satellites called ‘eyes in the sky’? Marks:2View AnswerAnswer:
Out of syllabus.
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Q9
An electric lamp is marked 100 W, 220 V. It is used for 5 hours daily. Calculate (i) Its resistance while glowing. (ii) Energy consumed in kWh per day. Marks:2View AnswerAnswer:
(i) Power (P) = (potential difference)2 / resistance P = V2 / R 100 = (220)2 / R R = 484 ohms. (ii) Energy consumed per day = power (P) x time (t) = 100 x 5 = 500 Wh = 0.5 KWh -
Q10
Point out differences between an artery and a vein. Marks:2View AnswerAnswer:
Differences between an artery and a vein are as follows: Arteries Veins 1. These are the blood vessels that carry blood from heart to the body parts. 1. These are the blood vessels that carry blood from body parts to the heart. 2. These carry oxygenated blood. 2. These carry deoxygenated blood.
