Suppose three equal charges, each equal to +q, are placed at the vertices of an equilateral triangle of side l. The net force exerted on a charge Q (with the same sign as q) placed at the centroid of the triangle is:

The 'Drain of Wealth' theory was propounded by which Indian nationalist leader?

Which event is considered the turning point in Mahatma Gandhi's leadership in the Indian independence movement?

Which African leader is known for his non-violent opposition to colonial rule?