Answer:
a) ![\Delta s=443037.9747\ J.K^{-1}](https://tex.z-dn.net/?f=%5CDelta%20s%3D443037.9747%5C%20J.K%5E%7B-1%7D)
b) ![\Delta s=31868131.8681\ J.K^{-1}](https://tex.z-dn.net/?f=%5CDelta%20s%3D31868131.8681%5C%20J.K%5E%7B-1%7D)
Explanation:
a)
Given:
amount of heat transfer occurred,![dQ=3.5\times 10^6\ J](https://tex.z-dn.net/?f=dQ%3D3.5%5Ctimes%2010%5E6%5C%20J)
initial temperature of car, ![T_i=36.5+273=309.5\ K](https://tex.z-dn.net/?f=T_i%3D36.5%2B273%3D309.5%5C%20K)
final temperature of car, ![T_f=44.4+273=317.4\ K](https://tex.z-dn.net/?f=T_f%3D44.4%2B273%3D317.4%5C%20K)
We know that the change in entropy is given by:
![\Delta s=\frac{dQ}{T_f-T_i}](https://tex.z-dn.net/?f=%5CDelta%20s%3D%5Cfrac%7BdQ%7D%7BT_f-T_i%7D)
(heat is transferred into the system of car)
![\Delta s=443037.9747\ J.K^{-1}](https://tex.z-dn.net/?f=%5CDelta%20s%3D443037.9747%5C%20J.K%5E%7B-1%7D)
b)
amount of heat transfer form the system of house,
initial temperature of house, ![T_i=23.5+273=296.5\ K](https://tex.z-dn.net/?f=T_i%3D23.5%2B273%3D296.5%5C%20K)
final temperature of house, ![T_f=5.3+273=278.3\ K](https://tex.z-dn.net/?f=T_f%3D5.3%2B273%3D278.3%5C%20K)
![\Delta s=\frac{dQ}{T_f-T_i}](https://tex.z-dn.net/?f=%5CDelta%20s%3D%5Cfrac%7BdQ%7D%7BT_f-T_i%7D)
![\Delta s=\frac{5.8\times 10^8}{278.3-296.5}](https://tex.z-dn.net/?f=%5CDelta%20s%3D%5Cfrac%7B5.8%5Ctimes%2010%5E8%7D%7B278.3-296.5%7D)
![\Delta s=31868131.8681\ J.K^{-1}](https://tex.z-dn.net/?f=%5CDelta%20s%3D31868131.8681%5C%20J.K%5E%7B-1%7D)
Answer:
![q=1\times10^{-8}C](https://tex.z-dn.net/?f=q%3D1%5Ctimes10%5E%7B-8%7DC)
Explanation:
Let the charge on the ball bearing is q.
charge on glass bead, Q = 20 nC = 20 x 10^-9 C
Force between them, F = 0.018 N
Distance between them, d = 1 cm = 0.01 m
By use of Coulomb's law in electrostatics
![F=\frac{KQq}{d^{2}}](https://tex.z-dn.net/?f=F%3D%5Cfrac%7BKQq%7D%7Bd%5E%7B2%7D%7D)
By substituting the values
![0.018=\frac{9\times10^{9}\times20\times10^{-9}q}{0.01^{2}}](https://tex.z-dn.net/?f=0.018%3D%5Cfrac%7B9%5Ctimes10%5E%7B9%7D%5Ctimes20%5Ctimes10%5E%7B-9%7Dq%7D%7B0.01%5E%7B2%7D%7D)
![q=1\times10^{-8}C](https://tex.z-dn.net/?f=q%3D1%5Ctimes10%5E%7B-8%7DC)
Thus, the charge on the ball bearing is ![q=1\times10^{-8}C](https://tex.z-dn.net/?f=q%3D1%5Ctimes10%5E%7B-8%7DC)
Answer:
857.5 m
2.8583×10⁻⁶ seconds
Explanation:
Time taken by the sound of the thunder to reach the student = 2.5 s
Speed of sound in air is 343 m/s
Speed of light is 3×10⁸ m/s
Distance travelled by the sound = Time taken by the sound × Speed of sound in air
⇒Distance travelled by the sound = 2.5×343 = 857.5 m
⇒Distance travelled by the sound = 857.5 m
Time taken by light = Distance the light travelled / Speed of light
![\text{Time taken by light}=\frac{857.5}{3\times 10^8}\\\Rightarrow \text{Time taken by light}=2.8583\times 10^{-6}](https://tex.z-dn.net/?f=%5Ctext%7BTime%20taken%20by%20light%7D%3D%5Cfrac%7B857.5%7D%7B3%5Ctimes%2010%5E8%7D%5C%5C%5CRightarrow%20%20%5Ctext%7BTime%20taken%20by%20light%7D%3D2.8583%5Ctimes%2010%5E%7B-6%7D)
Time taken by light = 2.8583×10⁻⁶ seconds
Answer:
B yes when displacement is negative