Day 217: CBSE Class 10 Science

5 questions (8 parts). Try each one first, then open its answer.

Question 1
Light — Reflection and Refraction. Asked once: 2023 (same type asked 4 times)
30 (b) $A convex lens can form a (i) real, inverted and magnified image as well as (ii) virtual, erect and magnified image of an object. If the focal length of the lens is 10 cm, what should be the range of the object distance in both cases ? Draw ray diagrams to justify your answer.$
Question 2 (case study, 4 parts)
Metals and Non-metals. Asked once: 2023 (same type asked 4 times)
Metals are required for a variety of purposes. For this we need their extraction from their ores. Ores mined from the earth are usually contaminated with many impurities which must be removed prior to the extraction of metals. The extraction of pure metal involves the following steps : (1) Concentration of ore (2) Extraction of the metal from the concentrated ore (3) Refining of the metal
37 (a) $Name an ore of Mercury and state the form in which Mercury is present in it.$
37 (b) $What happens to zinc carbonate when it is heated strongly in a limited supply of air ?$
37 (c) $\mathrm{Fe_2O_3}$
37 (c) OR $We cannot use carbon to obtain sodium from sodium oxide. Why ? State the reactions taking place at cathode and anode during electrolytic reduction of sodium chloride.$
Question 3
Our Environment. Asked once: 2023 (same type asked 4 times)
26 $How do harmful chemicals get accumulated progressively at each trophic level in a food chain ?$
Question 4
Our Environment. Asked once: 2024 (same type asked 4 times)
Two statements are given, one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the options given below.
20 $Assertion (A) : Oxygen is essential for all aerobic forms of life. Reason (R) : Free oxygen atoms combine with molecular oxygen to form ozone.$
Tap an option to check your answer.
Question 5
The Human Eye and the Colourful World. Asked once: 2023 (same type asked 4 times)
13 $In the following diagram showing dispersion of white light by a glass prism, the colours ‘P’ and ‘Q’ respectively are -$
Tap an option to check your answer.

Question 1

Question 2 (case study, 4 parts)

Question 3

Question 4

Question 5