The final image in an astronomical telescope is MCQ with Answer and Explanation

Explanation:
Control rods (made of cadmium, boron, or hafnium) absorb neutrons to regulate the fission chain reaction rate. Inserting rods deeper reduces neutron population, slowing reaction; withdrawing them increases reaction rate. Moderators (water, graphite) slow neutrons to thermal energies for efficient fission. Memory aid: 'Control rods = neutron absorbers; Moderators = neutron slowers'. This application question tests knowledge of reactor components, common in competitive exams. Always distinguish roles: fuel (fissionable material), moderator, control rods, coolant.

Explanation:
Wien's Displacement Law states that the wavelength at which a black body emits maximum radiation (lambda_m) is inversely proportional to its absolute temperature (T). lambda_m * T = b (Wien's constant). If the temperature T is doubled (2T), the peak wavelength lambda_m must strictly halve to maintain the constant product.

Explanation:
Loss in weight = buoyant force = 10 - 8 = 2 N. Weight of displaced water = 2 N. Volume of object = mass of displaced water / density. Archimedes principle.