PHYSICS 10 SCIENCE · 2026–27 · C · Constructed responses · QUESTION 21.5 · EM p. 197

Explain why background radiation is always present and how cosmic and terrestrial sources balance each other despite human-activity fluctuations.

وضاحت کریں کہ ماحول میں پس منظر کی اشعاع ہمیشہ کیوں موجود رہتی ہے اور انسانی سرگرمیوں کے اتار چڑھاؤ کے باوجود کائناتی و زمینی ذرائع کے باہمی توازن کے دعوے کا کیا مفہوم ہے؟

Solution & explanation

Natural radionuclides and cosmic particles provide persistent contributions. Their amounts vary with altitude, geology, buildings and activity. They add; there is no physical rule requiring equal or compensating contributions. The question’s word “balance” should not be taken as a conservation law.

Independent study answer. Original textbook ↗ · English-medium printed page 197.