Question

The length of needle floating on the surface of water is 1.5 cm. The force in addition to its weight required to lift the needle from water surface will be (surface tension of water = 7.5 N/cm) -
(1) 22.5 Newton (2) 2.25 Newton (3) 0.25 Newton (4) 225 Newton​

Answer 1

Mass or weight of the needle required for the answer. The force due to surface tension is 7.5×1.5=11.25Now for floating the we must haveweight = 11.25+extra upward forceNow knowing weight or mass we can calculate other force.

Answer 2

The force due to surface tension is = (7.5*1.5)N

                                                           = 11.25 N

Hey mate I think there is some wrong in the options.