The energy used by the light bulb in half an hour is 180000 J and the amount of thermal energy generated is 158400 J.
What is Energy?
Energy is the ability or the capacity to do work.
To calculate the energy of the light bulb we use the formula below
Formula:
- E = Pt.......... Equation 1
Where:
- E = Energy used by the bulb in a half-hour
- P = Power of the bulb
- t = Time
Given:
- P = 100 W
- t = 1/2 hour = 30 minutes = (30×60) = 1800 seconds
Substitute these values into equation 1
- E = (100×1800)
- E = 180000 J
- If the light converts 12% of electric energy to light energy, then 88% of the energy is used to generate thermal energy
Therefore,
- Thermal energy = (180000×88/100) = 158400 J
Hence, the energy used by the light bulb in half an hour is 180000 J and the amount of thermal energy generated is 158400 J.
Learn more about energy here: brainly.com/question/21927255
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First one is D and Second one is B
Answer:
(a) 0.063 m/s
(b) 1.01 m/s
Explanation:
rate of volume flow, V = 4 x 10^-6 m^3/s
(a) radius, r = 4.5 x 10^-3 m
Let the speed of blood is v.
So, V = A x v
where A be the area of crossection of artery
4 x 10^-6 = 3.14 x 4.5 x 10^-3 x 4.5 x 10^-3 x v
v = 0.063 m/s
Thus, the speed of flow of blood is 0.063 m/s .
(b) Now r' = r / 4 = 4.5 /4 x 10^-3 m = 1.125 x 10^-3 m
Let the speed is v'.
So, V = A' x v'
4 x 10^-6 = 3.14 x 1.125 x 10^-3 x 1.125 x 10^-3 x v'
v' = 1.01 m/s
Thus, the speed of flow of blood is 1.01 m/s .
