When a red giant has insufficient mass it pretty much sheds its outer layer to leave the center core know as the white dwarf
The efficiency of the scissor is 200%.
<u>Explanation:</u>
Efficiency is defined as the ratio of output of any instrument or device or machine to the input supplied to it. So the greater the output the greater will be the efficiency of the device.
As here the work done by us on the system is said to be 10 J so this will be equal to the input work done on the system. And the work done by the system i.e., the scissor is 20 J, so this will be the output work.
So, the efficiency is the ratio of output to input as shown below.
Efficiency = 
= 200
So, the efficiency of the scissor is 200%.
The farther apart the two objects, the weaker the gravitational attraction between them.
There are three types of heat conduction through substances. These are named as conduction,convection and radiation .here we have been given convection.
Convection is the type of mode of conduction of heat in which heat will flow though a liquid and gases due to the direct physical movement of particles.In this process the hotter particles will go upward as they become lighter and cooler,heavier particles come downward which after being heated up go upward .Hence a convectional current is formed for which whole of the liquid or gas gets heated.
There are different life examples of convection.
One may take an simple example of water in a container.The water molecules which are present bottom part of the container will be heated up first and go upward.The upper particles will come downward and they will constitute a convectional current.
Another life example is the flow of wind from one region to another region.the air at hotter region will become lighter and goes upward and the wind starts flowing from cold region region in order to occupy the vacant space.
Another example is the hot air balloon rising up..It is also another example of convection of heat
