<img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/RES_PHY_ELE_S01_001_S01.png" width="80%"> <br> If a charged body (+ve) is placed left side near a neutral conductor, (-ve) charge will induce at left surface and (+ve) charge will induce at right surface. Due to positively charged body -ve induced charge will feel attraction and the +ve induced charge will feel repulsion. but as the -ve induced charge is nearer, so the attractive force will be greater than the repulsive force. so the net force on the conductor due to positively charged body will be attractive. similarly, we can prove for nagatively charged body also. <br> From the above example we can conclude that. "A charged body can attract a neutral body". <br> If there is attraction between two bodies then one of them may be neutral. but if there is replusion between two bodies, both must be charged (similarly charged). So "repulsion is the test of electrification".