Question

An alpha particle enters a hollow tube of 4 m length with an initial speed of 1 km/s. It is accelerated in the tube and comes out of it with a speed of 9 km/s. The time for which it remains inside the tube is

विकल्प

• 8 × 10^–3 s

• 80 × 10^–3 s

• 800 × 10^–3 s

• 8 × 10^–4 s

Answer 1

8 × 10^–4 s

Explanation:

v² = u² + 2as

∴ (9000)² – (1000)² = 2 × a × 4

∴ a = 10⁷ m/s

Now t = `(v - u)/a`

∴ t = `(9000 - 1000)/10^7` = 8 × 10^–4 s