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Question 1

Anannya responded to the question: Why do electrical appliances with metallic bodies are connected to the mains through a three pin plug, whereas an electric bulb can be connected with a two pin plug? She wrote: Three pin connections reduce heating of connecting wires. (i) Is her answer correct or incorrect? Justify. (ii) What is the function of a fuse in a domestic circuit?

Question

Anannya responded to the question: Why do electrical appliances with metallic bodies are connected to the mains through a three pin plug, whereas an electric bulb can be connected with a two pin plug? She wrote: Three pin connections reduce ...

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CBSE Sample Paper 1 year 1 Answer 1009 views Tech Professional 18

Question 2

Assertion: Danger signals are made of red colour. Reason: Velocity of red light in air is maximum, so signals are visible even in dark.

Question

(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion. (b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion. (c) Assertion ...

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Class 10 science 3 years 1 Answer 836 views Enlightened 3

Question 3

The sample of soil from a particular place was tested for its pH value. It came out to be 5. Which one of the following should be added to the soil to make it suitable for the plant growth?

Question

i. Calcium chloride ii. Calcium Hydroxide iii. Calcium oxide Choose the correct option: a. Both (i) and (ii) b. Both (ii) and (iii) c. Only (i) d. Only (iii)

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Class 10 science 3 years 1 Answer 63 views Enlightened 2

Question 4

. Assertion: Chemical reaction changes the physical and chemical state of a substance. Reason: When electric current is passed through water (liquid), it decomposes to produce hydrogen and oxygen gases.

Question

(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion. · (b) Both Assertion and Reason are true but Reason is not the correct -explanation of Assertion. (c) Assertion is true but Reason is false.(d) ...

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Class 10 science 3 years 1 Answer 2196 views Enlightened 1

Question 5

Assertion: 34.12345 is a terminating decimal fraction Reason: Denominator of 34.12345, when expressed in the form q p , q ! 0, is of the form 2 5 m n , where m and n are nonnegative integers.

Question

(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion. (b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion. (c) Assertion ...

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Class 10 Maths 3 years 1 Answer 373 views Enlightened 1

Question 6

(i) State the law that explains the heating effect of current with respect to the measurable properties in an electrical circuit. (ii) List the factors on which the resistance of a conductor depends.

Question

(i) State the law that explains the heating effect of current with respect to the measurable properties in an electrical circuit. (ii) List the factors on which the resistance of a conductor depends.

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CBSE Sample Paper 1 year 1 Answer 1584 views Tech Professional 1

Question 7

Assertion: Highly reactive metals are obtained by electrolytic reduction of their molten ore. Reason: Highly reactive metals can be extracted by chemical reduction.

Question

(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion. (b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion. (c) Assertion ...

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Class 10 science 3 years 1 Answer 1931 views Enlightened 1

Question 8

You must have observed that iron articles are shiny when new, but get coated with a reddish brown powder when left for some time. This process is commonly known as rusting of iron. Some other metals also get tarnished in this manner. Have you noticed the colour of the coating formed on copper and silver? When a metal is attacked by substances around it such as moisture, acids, etc., it is said to corrode and this process is called corrosion. The black coating on silver and the green coating on copper are other examples of corrosion

Question

(i).Chemically rust is (a).only ferric oxide (b).hydrated ferric oxide (c).hydrated ferrous oxide (ii).Rusting of iron involves a chemical reaction which is a combination of: (a) Reduction as well as combination reactions (b) Oxidation as well as combination reactions (c) Oxidation as well ...

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Class 10 science 3 years 1 Answer 530 views Enlightened 1

Question 9

Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.

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Class 10 science 3 years 1 Answer 96 views Tech Professional 1

Question 10

Reactive metals can displace less reactive metals from their compounds in solution or molten form. all metals are not equally reactive. We checked the reactivity of various metals with oxygen, water and acids. But all metals do not react with these reagents. Displacement reactions give better evidence about the reactivity of metals. It is simple and easy if metal A displaces metal B from its solution, it is more reactive than B. The reactivity series is a list of metals arranged in the order of their decreasing activities.

Question

(i).Which of the following is the correct arrangement of the given metals in dscending order of their reactivity? Zinc, Iron, Magnesium, Sodium (a)Sodium > Magnesium > Zinc > iron (b) Sodium > Magnesium > Zinc > iron (c) Sodium > ...

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Class 10 science 3 years 1 Answer 42 views Enlightened 1

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