Answer:
a) 2.85 kW
b) $ 432
c) $ 76.95
Explanation:
Average price of electricity = 1 $/40 MJ
Q = 20 kW
Heat energy production = 20.0 KJ/s
Coefficient of performance, K = 7
also
K=(QH)/Win
Now,
Coefficient of Performance, K = (QH)/Win = (QH)/P(in) = 20/P(in) = 7
where
P(in) is the input power
Thus,
P(in) = 20/7 = 2.85 kW
b) Cost = Energy consumed × charges
Cost = ($1/40000kWh) × (16kW × 300 × 3600s)
cost = $ 432
c) cost = (1$/40000kWh) × (2.85 kW × 200 × 3600s) = $76.95
Answer:
. Doppler ultrasound is based on absorption of sound, and other
ultrasound technology is based on reflection.D.
Explanation:
Answer:
Explanation:
It is given that,
The number of lines per unit length, N = 900 slits per cm
Distance between the formed pattern and the grating, l = 2.3 m
n the first-order spectrum, maxima for two different wavelengths are separated on the screen by 2.98 mm, 
Let d is the slit width of the grating,
For the first wavelength, the position of maxima is given by :
For the other wavelength, the position of maxima is given by :
So,
or
So, the difference between these wavelengths is 14.3 nm. Hence, this is the required solution.
Answer:
(d) a net external force must be acting on the system
Explanation:
Momentum is given as the product of mass and velocity.
P = MV
According to Newton's second law of motion, " Force applied to a body (system) is directly proportional to the rate of change of momentum of the body (system) which takes place in the direction of the applied force (external force).
F ∝ΔMV
Therefore, If the total momentum of a system is changing, a net external force must be acting on the system.
(d) a net external force must be acting on the system
