Explanation

• A Unijunction Transistor (UJT) has one junction.
• It is commonly used in triggering circuits for thyristors and other semiconductor devices.

Explanation

When capacitors are connected in parallel, the total capacitance (Ct) increases, as the effective plate area and charge storage capacity increase.

The formula for total capacitance in parallel is: Ct = C1 + C2 + ... + Cn

In series connection, the total capacitance decreases, as the effective plate area and charge storage capacity decrease.

The formula for total capacitance in series is: 1/Ct = 1/C1 + 1/C2 + ... + 1/Cn

Explanation

The critical angle is the angle of incidence above which total internal reflection occurs.

It can be calculated using Snell's law:

n1 sin(θ1) = n2 sin(θ2)

where n1 = 1.33 (refractive index of water), θ1 = critical angle, n2 = 1 (refractive index of air), and θ2 = 90° (angle of refraction).

Rearranging the equation to solve for θ1, we get:

θ1 = arcsin(n2 / n1)

Substituting the values, we get:

θ1 = arcsin(1 / 1.33) ≈ 48.8°

So, the critical angle is approximately 48.8°.

Explanation

When white light passes through a prism, it is refracted, or bent, and split into its individual colors, a process known as dispersion.

The order of deviation is:

• Violet (most deviated)
• Blue
• Green
• Yellow
• Red (least deviated)

Explanation

• Television remote controllers use infrared (IR) waves to transmit commands to the TV.
• IR waves are a type of electromagnetic radiation with a frequency too low to be seen by the human eye.
• They are widely used in remote control applications, such as:
• TV remote controls
• Air conditioners
• DVD players
• Garage door openers

Explanation

Evaporation is the process by which molecules escape from the surface of a liquid to become vapor, even if the liquid is below its boiling point.

This occurs when some molecules have enough energy to break free from the surface tension of the liquid and turn into vapor.

Key Points:

• Boiling occurs when a liquid is heated to its boiling point, causing bubbles to form and rise to the surface.
• Condensation is the process by which vapor is converted back into a liquid.
• Convection is the transfer of heat through the movement of fluids.

Explanation

According to Raoult's Law, the relative lowering of vapor pressure for a solution is equal to the mole fraction of the solute. 

Raoult's Law states that the vapor pressure of a solvent in a solution is equal to the vapor pressure of the pure solvent multiplied by its mole fraction in the solution.

Therefore, the relative lowering of vapor pressure, which is the difference between the vapor pressure of the pure solvent and the vapor pressure of the solution, is directly proportional to the mole fraction of the solute. 

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

In a metallic conductor, current flows due to the movement of free electrons in the conduction band.

These electrons drift under the influence of an electric field, creating electric current.

Explanation

Frictional force is a non-conservative force.

Unlike conservative forces (such as elastic spring force, gravitational force, and electric force), friction dissipates energy as heat and does not store it.

It means the work done by friction depends on the path taken.