Isotopes differ in the number of: MCQ with Answer and Explanation

Isotopes differ in the number of:
A. Electrons
B. Positrons
C. Neutrons
D. Protons
Answer: Option C
Solution (By JKSSB Mock Tests)
Isotopes are atoms of the same element with the same atomic number (protons) but different mass numbers due to varying number of neutrons. For example, protium (¹H) has 0 neutrons, deuterium (²H) has 1, tritium (³H) has 2. Chemical properties are nearly identical because electronic configuration is the same, but physical properties (mass, density) differ.

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The chemical formula of nitric acid is:
A. HCl
B. H₂SO₄
C. HNO₃
D. H₃PO₄

Correct Answer: Option C


Explanation:
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Cement mixed with aggregates (sand, gravel) and water forms:
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Correct Answer: Option C


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The unit of calorific value is:
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B. m/s
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Correct Answer: Option C


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