<u>Answer</u>
8. 2 Hz
9. 0.5 seconds
10. 20 cm
<u>Explanation</u>
<u>Q 8</u>
Frequency is the number of oscillation in a unit time. It is the rate at which something repeats itself in a second.
In this case, the spring bob up and down 2 times per second.
∴ Frequency = 2 Hz
<u>Q 9</u>
Period is the time taken to complete one oscillation.
2 oscillations takes 1 second
1 oscillation = 1/2 seconds.
∴ Period = 0.5 seconds
<u>Q 10</u>
Amplitude is the the maximum displacement of the spring.
In this case the spring bob up 20 cm. This is it's displacement.
∴ Amplitude = 20 cm
Answer:
c. is more than that of the fluid.
Explanation:
This problem is based on the conservation of energy and the concept of thermal equilibrium

m= mass
s= specific heat
\DeltaT=change in temperature
let s1= specific heat of solid and s2= specific heat of liquid
then
Heat lost by solid= 
Heat gained by fluid=
Now heat gained = heat lost
therefore,
1000 S_2=800 S_1
S_1=1.25 S_2
so the specific heat of solid is more than that of the fluid.
Answer:
Lenz's law, in electromagnetism, statement that an induced electric current flows in a direction such that the current opposes the change that induced it. This law was deduced in 1834 by the Russian physicist Heinrich Friedrich Emil Lenz (1804–65).
The middle or centre of the Earth is the core. However the middle of the layers from the surface to the centre of the Earth is known as mantle.