Mirage is an optical illusion observed in hot deserts. It is entirely caused by: MCQ with Answer and Explanation

Explanation:
Alpha particles heavy, slow, high ionisation.

Explanation:
Moderator slows neutrons via elastic collisions, low absorption. Heavy water, graphite.

Explanation:
Inside a long solenoid, magnetic field is uniform (constant magnitude and direction), parallel to the axis, given by B = μ₀nI, where n is turns per unit length. Outside, field is nearly zero. This uniformity makes solenoids useful for creating controlled magnetic fields. Memory tip: 'Solenoid: uniform B inside like bar magnet'. This conceptual question tests knowledge of magnetic field configurations, crucial for electromagnetism in competitive exams. Always distinguish solenoid field (uniform inside) from straight wire field (circular, non-uniform).