An old man wanted to leave all of his money to one of his three sons, but he didn't know which one he should give it to. he gave each of them a few coins and told them to buy something that would be able to fill their living room. the first man bought straw, but there was not enough to fill the room. the second bought some sticks, but they still did not fill the room. the third man bought two things that filled the room, so he obtained his father's fortune. what were the two things that the man bought?

Which statement is true for light passing into a medium that is more optically dense than the first medium through which it past

In a thunderstorm, charge builds up on the water droplets or ice crystals in a cloud. thus, the charge can be considered to be distributed uniformly throughout the cloud. for the purposes of this problem, take the cloud to be a sphere of diameter 1.00 kilometer. the point of this problem is to estimate the maximum amount of charge that this cloud can contain, assuming that the charge builds up until the electric field at the surface of the cloud reaches the value at which the surrounding air breaks down. this breakdown means that the air becomes highly ionized, enabling it to conduct the charge from the cloud to the ground or another nearby cloud. the ionized air will then emit light due to the recombination of the electrons and atoms to form excited molecules that radiate light. in addition, the large current will heat up the air, resulting in its rapid expansion. these two phenomena account for the appearance of lightning and the sound of thunder. take the breakdown electric field of air to be eb=3.00ă—106n/c. part a estimate the total charge q on the cloud when the breakdown of the surrounding air is reached. express your answer numerically, to three significant figures, using ďµ0=8.85ă—10â’12c2/(nâ‹…m2) .

Crowbar of 5 metre is used to lift an object of 800 metre if the effort arm is 200cm calculate the force applied