Answer:
Current amplitude, I = 5.57 A
Explanation:
It is given that,
Effective resistance, R = 22 ohms
Inductive reactance, L = 72 ohms
Voltage of the alternating source, V = 420 volt
The total impedance of the RL circuit is given by :


Z = 75.28 ohms
From Ohm's law,



I = 5.57 A
So, the current amplitude of the electric motor is 5.57 A. Hence, this is the required solution.
Answer : The time taken for the concentration will be, 7.98 seconds
Explanation :
First order reaction : A reaction is said to be of first order if the rate is depend on the concentration of the reactants, that means the rate depends linearly on one reactant concentration.
Expression for rate law for first order kinetics is given by :
![k=\frac{2.303}{t}\log\frac{[A]_o}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA%5D_o%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for the process = ?
= initial concentration = 0.860 M
= concentration after time 't' = 0.260 M
Now put all the given values in above equation, we get:


Therefore, the time taken for the concentration will be, 7.98 seconds
Answer:The total variation in the amount of light entering our eye is not dectiable therefore planets do not twinkle.
Explanation:Stars twinkle, while planets (usually) shine steadily. Why? Stars twinkle because … they're so far away from Earth that, even through large telescopes, they appear only as pinpoints. ... Planets shine more steadily because … they're closer to Earth and so appear not as pinpoints, but as tiny disks in our sky.As light from a star races through our atmosphere, it bounces and bumps through the different layers, bending the light before you see it. Since the hot and cold layers of air keep moving, the bending of the light changes too, which causes the star's appearance to wobble or twinkle.
The earth has an atmosphere that disintegrates most meteorites that make craters, unlike the moon, which has no atmosphere and nothing to protect it from meteorites