Explanation

The number of loops in stationary waves depends on the wavelength of the waves. 

A longer wavelength means fewer loops fit within a given length, and vice versa, so the number of loops is directly related to the wavelength. 

Explanation

The total energy of a hydrogen atom in its ground state is negative. 

The energy of a hydrogen atom in its ground state is typically represented as -13.6 eV.

A negative energy value indicates that the electron is bound to the nucleus and requires energy to be overcome to escape.

The ground state is the lowest energy level an electron can occupy in a hydrogen atom. 

Explanation

The reverse process of the photoelectric effect is the production of X-rays when electrons are decelerated.

In the photoelectric effect, light (photons) interacts with a material, causing electrons to be emitted.

Explanation

The SI unit of conductance is the Siemens (S).

It is the reciprocal of resistance, which is measured in ohms (Ω).

Therefore, 1 Siemens is equal to 1/ohm.

The term "mho" is also sometimes used as a unit of conductance, but Siemens is the standard SI unit. 

Explanation

The efficiency of a Carnot engine is defined as the ratio of the heat absorbed from the hot reservoir (heat accepted) to the heat rejected to the cold reservoir (heat rejected).

This efficiency is directly related to the temperature difference between the two reservoirs. 

Explanation

A heat engine operating in reverse is called a heat pump or a refrigerator.

Essentially, these devices move heat from a cooler area to a warmer area, requiring external work to do so, which is the opposite of how a heat engine functions. 

Explanation

The wave velocity in any medium depends on all of the above:

Elasticity:

A medium's elasticity determines how easily it can resist deformation and return to its original shape when force is applied.

Higher elasticity means the wave can travel faster through the medium. 

Density:

The density of a medium also affects wave velocity.

Denser media tend to slow down wave propagation. 

Homogeneity:

A homogeneous medium has consistent properties throughout, meaning the wave velocity will be uniform in all directions. 

Explanation

Speed = 3000 RPM (revolutions per minute)

Step 1: Convert RPM to revolutions per second (RPS)

Step 2: Convert revolutions to radians

Since 1 revolution = 2π radians:

50 rev/sec×2π= 100π radians/sec

Explanation

The ball will fall behind him.

When the man throws the ball vertically upward, it maintains the horizontal velocity of the train due to inertia.

However, the train continues to move forward while the ball is in the air.

As the ball falls back down, it will have traveled a shorter horizontal distance compared to the train,

Resulting in it landing behind the man where he originally threw it. 

Explanation

Momentum (p) is defined as mass (m) multiplied by velocity (v), so p = mv.

If we square p and divide by m, we get: p^2/m = (mv)^2/m = mv^2.

This is the formula for kinetic energy.

Therefore, p^2/m has the same unit as energy.