Physics Questions

Gear finishing operation is called Burnishing.

The usual cause of sea breeze is the difference in specific heat capacity between land and water Land heats and cools more quickly than water.

What is the cause of a sea breeze?

The air over the land is warmed and rises, to a greater temperature than that over the sea. This produces a convection current, with cooler air flowing in from over the sea to replace that rising from the land. At night the land cools more than the sea, so the action reverses to produce a land-breeze, blowing off the land.

without this centripetal force, circular motion is not possible. It acts radially towards the centre and if this force is removed there will be no circular motion but the revolving body will fly off at a tangent.

Projectile

Black  surfaces are good emitters of heat ( They are also good absorbers of heat). If the black surface is rough too, the emitting will be better. So (b) is the correct answer. Shining surfaces reflect back radiation. So if the black surface is also shining the effectiveness of emitting heat is lessened.

Phototropism is the ability of a photosynthesizing organism, to grow directionally in response to a light source. It is very common in plants, but can also occur in other organisms such as fungi.

Example :: Sunflower

A Mixture is a material made up of two or more different substances which are mixed.

Mixtures can be either homogeneous or heterogeneous.

* A homogeneous mixture is a type of mixture in which the composition is uniform and every part of the solution has the same properties.

* A heterogeneous mixture is a type of mixture in which the components can be seen, as there are two or more phases present.

Air is a homogeneous mixture of the gaseous substances nitrogen, oxygen, and smaller amounts of other substances.

1 atm: It was originally defined as the pressure exerted by 760 mm of mercury at 0 °C and standard gravity (g = 9.80665 m/s2).