Answer:
There are two similarities between refracting telescope and compound microscope.
1. both have objective lens and eyepiece lens
2. both the lenses are convex in nature.
Explanation:
Objective lens is near the object and eyepiece is near the eye through which we can see the image.
Convex or converging lens is used to converge the rays of light coming from the object.
They both have an objective lens and an eyepiece lens.
b) What is the minimum amount of electrical energy required bythe refrigerator to carry out this process if it operates betweenreservoirs at temperatures of 20.0 °C and -20.0 °C?
Answer:
(a)
(b) 556464 joule
Explanation:
Given:
The conversion of water of 20.0 °C to the ice of –20.0 °C will comprise of three steps:
We have,
(a)
Now, total heat lost in the process:
where:
= change in temperature of ice and water respectively.
is the total heat extracted during the process.
(b)
So, 556464 joule is the minimum electrical energy (by the law of energy conservation under no loss condition) required by refrigerator to carry out this process if it operates between the reservoirs at temperatures of 20.0 °C and -20.0 °C, because for a refrigerator to work in a continuous cycle it is impossible to transfer heat from a low temperature reservoir to a high temperature reservoir without consuming energy in the form of work. Here 556464 joule is the heat of the system to be eliminated.
The amount of heat extracted from the water involves the sum of heat lost as it cools and then freezes. The minimum energy needed by the refrigerator to do this is given by the formula for Carnot efficiency.
To answer these questions, we'll need to understand some fundamental principles of thermodynamics.
a) The heat Q taken from the water will be the sum of the heat released during cooling of the water until 0.0°C, and the heat released during freezing at 0.0°C. The heat loss as the water cools can be calculated using Q = mcΔt where m=mass of water, c=specific heat of water, and Δt=change in temperature. The heat loss as water freezes can be calculated using Q = mlf where lf is the latent heat of fusion. Adding these two quantities gives the total heat extracted.
b) The minimum energy needed by the refrigerator, W, is given by the Carnot efficiency formula, W = Q*(T_hot - T_cold)/T_hot, where T is in Kelvin. This would tell you how much energy the refrigerator needs to remove the heat from the water and cool it down to the freezer temperature.
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b. a decrease in the frequency of the sound wave.
c. an increase in the frequency of the sound wave.
d. an increase in the amplitude of the sound wave.
B) 880 amps
C) 8.3 amps
D) 0.120 amps
Answer : I = 8.33 A
Explanation :
It is given that,
Power rating of the toaster, P = 1000 watts
Household voltage, V = 120 volts
We know the relation between power, voltage and the current is :
8.33 A of current runs through the toaster.
Hence, this is the required solution.