Answer:
12500W
Explanation:
Given parameters:
Work done = 250000J
Time taken = 20s
Unknown:
Power of the crane = ?
Solution:
Power is the defined as the rate at which work is being done;
Mathematically;
Power = 
insert the parameters and solve;
Power = 
= 12500W
Heat can be given to a substance without raising its temperature,When a substance is changing its physical state[for eg from solid to liquid and liquid to gas ]. The heat energy which has to be supplied to change the state of substance is called its Latent Heat. Latent heat does not raise the temperature .
Answer:
Explanation: The equation that relates resistance of tungsten at different temperatures is as follows
R = R₀ [1 + α ∆T] , R₀ is resistance at lower temperature , R is resistance at higher temperature . α is temperature coefficient of resistivity and ∆T is rise in temperature .
Putting the values
170 = 26 [1 + .0045 ∆T]
∆T = 1230.75
lower temperature = 40◦C
higher temperature = 1230 + 40
= 1270◦C
Semi anthracite has the higest which is 29.5
