Answer:
The magnitude of the current is 5.45 mA.
Explanation:
Given that,
Resistance = 10.0 ohm
Radius = 0.10 m
Magnetic field = 1.0 T
Angle = 30°
Increase magnetic field = 7.0 T
Time t = 3.0 s
Number of turns = 1
We need to calculate the initial flux
Using formula of flux

Put the value into the formula



We need to calculate the final flux


We need to calculate the induced emf
Using formula of emf

Put the value into the formula


We need to calculate the current
Using formula of current

Put the value into the formula


Hence, The magnitude of the current is 5.45 mA.
Precision refers to the closeness of two or more measurements to each other. Using the example above, if you weigh a given substance five times, and get 3.2 kg each time, then your measurement is very precise. Precision is independent of accuracy.
Answer:
The correct option is;
(c) 64W
Explanation:
Here we have the Coefficient Of Performance, COP given by

The heat change from 23° to 6°C for a mass of 10 kg/h which is equivalent to 10/(60×60) kg/s or 2.78 g/s we have
= m·c·ΔT = 2.78 × 4.18 × (23 - 6) = 197.39 J
Therefore, plugging in the value for
in the COP equation we get;
which gives

Since we were working with mass flow rate then the power input is the same as the work done per second and the power input to the refrigerator = 63.674 J/s ≈ 64 W.
The power input to the refrigerator is approximately 64 W.
The whistle you use to call has a frequency of 21 kHz, so you do not recognize it also because your threshold of hearing is only 20 kHz. Since you are unable to hear sounds above this value, you request your friend to blow the whistle and move farther away. The frequency will decrease due to Doppler effect.