(a) 
<u>Explanation:</u>
Given:
Moment of Inertia of m₁ about the axis, I₁ = m₁x²
Moment of Inertia of m₂ about the axis. I₂ = m₂ (L - x)²
Kinetic energy is rotational.
Total kinetic energy is 
Work done is change in kinetic energy.
To minimize E, differentiate wrt x and equate to zero.
Alternatively, work done is minimum when the axis passes through the center of mass.
Center of mass is at 
Answer:
By observing the color of lines in the spectrum.
Explanation:
There are two types of lines in the spectrum explained below:
i) Bright lines: Bright lines occurs on the spectrum when atoms emit photons. These bright lines show the emission line spectrum.
ii) Dark Lines: Dark lines occurs on the spectrum when atoms absorb photons. These black lines show the absorption line spectrum.
Hence, by observing the color of lines it is possible to identify emission line spectrum and absorption line spectrum.
Answer:
Electromagnetic waves or EM waves are waves that are created as a result of vibrations between an electric field and a magnetic field.
Answer:
b) The more could in the solenoid of the primary loop of a transformer will induce a greater emf in the secondary loop.
Explanation:
I think what that option was saying was the closer to the magnet the solenoid is, the faster it is going and the greater is the magnetic field due to the magnet in the vicinity of the solenoid, so the emf increases.
The answer is Basalt have similar chemistries.
