The least count of a vernier calliper is 0.01 cm. A measurement should be recorded as MCQ with Answer and Explanation

Explanation:
Beta (β) rays are streams of high-speed electrons (β⁻) or positrons (β⁺) emitted during radioactive decay. Beta-minus decay: neutron → proton + electron + antineutrino. Alpha rays are helium nuclei (²He⁴); gamma rays are high-energy photons; neutrons are neutral particles. Memory tip: 'Beta = electrons; Alpha = He nucleus; Gamma = photons'. This classification question tests knowledge of radioactivity types, crucial for modern physics in competitive exams. Always distinguish penetration power: alpha < beta < gamma.

Explanation:
A rocket works on the principle of conservation of linear momentum. As the exhaust gases are expelled downward at high velocity, they carry downward momentum. To conserve the total momentum of the system (which is initially zero), the rocket must acquire an equal and opposite (upward) momentum, propelling it forward.

Explanation:
Apparent weight = m(g+a) = 60×(10+2) = 720 N, which corresponds to 72 kg mass on scale (if scale calibrated in kg under g=10). Reading 72 kg. Downward acceleration would reduce.