Answer:
A) incandescent ligth bulb, its efficiency is about 10%
Explanation:
The incandescent bulb, that is, the well-known focus with its warm light, was one of the most useful inventions of the 19th century although its use is currently considered very inefficient. These lamps waste between 80 and 90 percent of the total electricity they consume by turning it into heat. The metal filament thus heated and which is the central part of the bulb, only converts the remaining energy into light. Its service life ranges from 750 to 1,000 hours.
This is why they are used in ovens for food preparation, because of the large amount of heat they generate.
The steam boiler in a power plant depends on the fuel that it is using, but a coal-fired power plant with modern technology its efficiency is about 40%
Electric motor are around 85-92%
In order to better understand the concept of efficiency it is as if we pay 100 dollars of gasoline for our weekly use, but of that 100 dollars the car only uses 10 dollars to do that activity the rest of the money the 90 dollars were lost because of the inefficiencies of the vehicle.
Answer:D
Explanation:according to the law of conservation of energy/momentum, when two bodies collides, their total momentum and energy before and after collision are equal. Given that the two bodies move with the same velocities after collision, means that the law has not been violated since momentum = mass x velocity (where mass is constant)
Answer: (b)0.000012/k
Explanation:
The linear expansion of the metal rod is given by
where
is the linear expansion
is the initial length of the rod
is the linear expansivity
is the increase in temperature
By re-arranging the equation, we find the linear expansivity:
