The correct answer is D. Amount of time and area of physical contact between the substances.
Explanation:
Heat transfer refers to the flow of thermal energy or heat between two or more objects. This process involves multiple factors and implies heat from the hottest object goes to the coldest one until there is an equilibrium. To begin, heat transfer depends on the amount of thermal energy in the objects because objects must have a different amount of thermal energy for heat to flow.
Besides this, the amount of energy that flows depends on the time and the contact between the substances of objects. Indeed, objects need to be in contact or close to each other for heat to transfer, and the time needs to be enough for the process to occur. For example, if you place a pot over the fire just for a few seconds it is likely the heat transferred is minimal, which does not occur if you leave the pot more time. At the same time if the pot is in close contact with fire more heat will be transferred.-
Metals in general, are good heat conductors
Answer:
So the ratio will be 
Explanation:
We have given heat engine absorbs 450 joule from high temperature reservoir
So 
As the heat engine expels 290 j
So work done W = 290 J
We know that efficiency 
It is given that efficiency of the engine only 55 % of Carnot engine
So efficiency of Carnot engine 
Efficiency of Carnot engine is 
-- The long line and short line close together at the left side
of the diagram represent a single-cell battery.
It's the only one in this diagram.
It's a device that stores chemical energy and delivers it on demand.
-- The zig-zag lines with circles around them represent light bulbs.
There are three of them in this diagram.
They are devices used to produce light by dissipating electrical energy.
-- The zig-zag lines without circles, at the top of the diagram,
represent resistors.
There are two of them in this diagram.
They are devices used to change or control electrical parameters
within a circuit by dissipating electrical energy.
-- The short straight line between two small circles at the bottom
of the diagram represents a switch.
There is only one switch in this circuit.
It's a device used to easily and quickly start or stop the flow of current
past a certain point in a circuit.
In this circuit ...
-- When the switch is closed (as drawn), the light bulb nearest the battery
glows brightest, the light bulb in the middle glows less bright, and the light
bulb on the right side glows dimmest of all.
-- When the switch is open, the light bulb nearest the battery glows, and
neither of the other two light bulbs glows at all.
