Explanation

In a line absorption spectrum, dark lines are due to transmittance.

In an absorption spectrum, dark lines appear against a continuous background.

These dark lines correspond to wavelengths of light that have been absorbed by the material through which the light passes.

The remaining wavelengths, which are not absorbed, are transmitted and create the bright background. 

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 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

A cell counter is a device specifically designed to count the number of cells in a suspension.

This is crucial in cell culture experiments, as researchers need to know the cell concentration before seeding or performing other procedures. 

Explanation

The range of a projectile is the same for two complementary launch angles (i.e., they add up to 90°).

For example, a projectile launched at 30° and 60° will have the same range.

Explanation

 The charge of cathode ray particles can be determined by passing them through oppositely charged plates. 

Cathode rays are composed of negatively charged particles called electrons.

When these rays pass through an electric field with oppositely charged plates

They are deflected towards the positively charged plate, demonstrating their negative charge. 

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

With an increase in the number of unpaired electrons, paramagnetism increases. 

Paramagnetism is directly related to the presence of unpaired electrons.

More unpaired electrons mean a stronger magnetic field, hence a greater degree of paramagnetism. 

Explanation

 The enthalpy change during the formation of one mole of a compound from its elements in their standard states is called standard heat of formation. 

Explanation

Ethics is a branch of philosophy that deals with questions of morality, considering what is considered right or wrong actions.