Question Discussion & Solution

The given group is all the Forms of energy. Leaping frog is mechanical energy, melting ice cream is thermal energy, and Radio wave is a type of Electromagnetic energy.

Out of the given alternatives lightning is a type of electrical energy.

CONCEPT:

• Supersonic speed: An object moving with a speed greater than the speed of sound is said to move with a supersonic speed.
  • Generally, a bullet fired from a gun and aircraft moves with supersonic speed. 
  • The speed of sound is about 768 miles per hour (1,236 kilometers per hour) at sea level.
• Supersonic speeds are described by their "Mach number".
• Mach number: The ratio of the speed of the object to the speed of sound in the air of the same temperature and density is called Mach number.
  • Supersonic includes speeds up to five times faster than the speed of sound, or Mach 5.

EXPLANATION:

• When the speed of any object exceeds the speed of sound, it is said to be traveling at Supersonic speed. So option 2 is correct.

EXTRA POINTS:

• Subsonic has a speed of less than 0.8 Mach.
• Hypersonic may have a speed between 5-10 Mach.

Five students – M, Q, U, X, and Z are compared.

1. Weight of Z is less than only two students. _ > _ > Z > _ > _

2. Weight of Q is greater than Z and Weight of Q is less than only U.

U > Q > Z

From 1 and 2, we get:

U > Q > Z > M/X > M/X

The correct answer is 68 Assembly Constituencies.

• As of June 2020, the state of Himachal Pradesh has been divided into 68 Assembly Constituencies.

Key Points

• Himachal Pradesh:
  • In 1970, the Union Territory of Himachal Pradesh was elevated to the status of the state.
  • Its summer capital is Shimla.
  • Its winter capital is Dharamshala.
  • It has a total of 4 Lok Sabha seats and 3 Rajya Sabha seats.
  • Current Governor: Bandaru Dattatreya
  • Current Chief Minister: Jai Ram Thakur

CONCEPT:

• Power is the ability to bend light and it is equal to the reciprocal of the focal length of the lens/mirror in meters.

Power (P) = 1/f

Where f is the focal length of the lens/mirror.

EXPLANATION:

As explained above, Dioptre is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres.

And since the S.I unit of the focal length is the meter (m).

So the S.I unit of power = 1/(SI unit of focal length) = m-1 = Dioptre (D).

1 m-1 = 1 D