Two waves interfering at a point have a path difference of lambda / 2. Their corresponding phase difference is exactly: MCQ with Answer and Explanation

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).

Explanation:
Convection requires medium, movement of hot and cold masses. Land/sea breeze, trade winds, heating water. Conduction vibration transfer without particle movement.

Explanation:
Iris adjusts pupil size.