Day 71: CBSE Class 10 Science

5 questions (11 parts). Try each one first, then open its answer.

Question 1
Light — Reflection and Refraction. This type asked 2 times: 2023, 2025. This one: 2025
13 $Mirror ‘X’ is used to concentrate sunlight in solar furnace and Mirror ‘Y’ is fitted on the side of the vehicle to see the traffic behind the driver. Which of the following statements are true for the two mirrors ? (i) The image formed by mirror ‘X’ is real, diminished and at its focus. (ii) The image formed by mirror ‘Y’ is virtual, diminished and erect. (iii) The image formed by mirror ‘X’ is virtual, diminished and erect. (iv) The image formed by mirror ‘Y’ is real, diminished and at its focus.$
Tap an option to check your answer.
Question 2 (case study, 4 parts)
Magnetic Effects of Electric Current. This type asked 2 times: 2023, 2025. This one: 2025
In our homes, we receive the supply of electric power through a main supply also called mains, either supported through overhead electric poles or by underground cables. In our country the potential difference between the two wires (live wire and neutral wire) of this supply is 220 V.
39 (a) $Write the colours of the insulation covers of the line wires through which supply comes to our homes.$
39 (b) $What should be the current rating of the electric circuit (220 V) so that an electric iron of 1 kW power rating can be operated ?$
39 (c) (i) $What is the function of the earth wire ? State the advantage of the earth wire in domestic electric appliances such as electric iron.$
39 (c) (ii) $List two precautions to be taken to avoid electrical accidents. State how these precautions prevent possible damage to the circuit/appliance.$
Question 3 (case study, 4 parts)
Magnetic Effects of Electric Current. This type asked 2 times: 2022, 2025. This one: 2025
In order to obtain magnetic field lines around a bar magnet, a student performed an experiment using a magnetic compass and a bar magnet. The magnet was placed on a sheet of white paper fixed on a drawing board. Using magnetic needle he obtained on the paper a pattern of magnetic field lines (as shown below) around the bar magnet.
39 (a) $By convention, the field lines emerge from north pole and merge at south pole. Why ? Give reason.$
39 (b) $State the relationship between strength of the magnetic field and the degree of closeness of the field lines.$
39 (c) (i) $(i) No two field lines can ever intersect each other. Give reason. (ii) The magnetic field in a given region is uniform. Draw a diagram to represent it.$
39 (c) (ii) $Draw the pattern of the magnetic field lines through and around a current carrying solenoid. What does the pattern of field lines inside the solenoid represent ?$
Question 4
Metals and Non-metals. This type asked 2 times: 2024, 2025. This one: 2025
4 $Aluminium powder is used in thermit welding because :$
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Question 5
Metals and Non-metals. This type asked 2 times: 2024, 2025. This one: 2025
21 $Name a metal found in the earth’s crust (i) in free state and (ii) in the form of its compound. State where each of these metals are placed in the reactivity series of metals.$

Question 1

Question 2 (case study, 4 parts)

Question 3 (case study, 4 parts)

Question 4

Question 5