Explanation

 If the temperature of the source of heat increases, the efficiency of a Carnot engine will increase.

The efficiency of a Carnot engine is directly related to the temperature difference between the hot and cold reservoirs.

A higher source temperature leads to a greater temperature difference and thus, a higher efficiency. 

Explanation

Sound waves diffract (bend) around corners, allowing us to hear them,

While light waves do not diffract as much, making it impossible to see around corners.

Diffraction is the bending of waves around obstacles or through openings.

Sound waves have longer wavelengths than light waves, which makes diffraction more noticeable for sound.

Polarization is a property of transverse waves, and while light waves can be polarized, sound waves cannot.

Dispersion is the separation of waves into different frequencies,

And while it can occur with light, it's not why we can hear around corners. 

Explanation

• Energy
• Momentum
• Charge

Explanation

A filament is a thin wire, typically made of tungsten, that is heated to produce a continuous flow of electrons.

When an electric current is passed through the filament, it heats up and releases electrons, creating a steady stream of electrons.

This principle is used in various devices such as vacuum tubes, cathode ray tubes (CRTs), and electron microscopes.

Explanation

The head-to-tail rule is a method for adding vectors, such as forces, by lining up the head of one vector with the tail of the next vector.

This rule can be used to add any number of forces, not just two or three.

Explanation

The transistor is a semiconductor device with at least three terminals.

These terminals are typically referred to as the :

• Emitter
• Base
• Collector

They allow the transistor to control the flow of electrical signals and power. 

Explanation

Total distance = Length of train + Length of bridge = 100 m + 200 m = 300 m  

Speed = 15 m/s  

Time = Distance / Speed = 300 / 15 = 20 seconds

Explanation

A body moving in a circular path with constant speed has variable acceleration. 

While the speed remains constant, the direction of the velocity vector is constantly changing as the body moves around the circle.

Since acceleration is the rate of change of velocity, and velocity is changing (even though speed is constant),

The body experiences a constant magnitude of acceleration

But the direction of that acceleration changes at every point on the circle.

This makes the acceleration variable. 

Explanation

 A device based on the photoelectric effect is called a photodiode. 

 A photodiode is a semiconductor device that converts light into electrical current by absorbing photons and generating electron-hole pairs, essentially utilizing the photoelectric effect. 

Explanation

Given:

• Radius of the circle$r=4$ meters

• Arc length (distance along the circumference), $s=14$ meters

We are to find the displacement, which is the straight-line distance between the starting and ending points of the arc.

Step 1: Find the angle subtended by the arc at the center (θ in radians):

$$theta = frac{s}{r} = frac{14}{4} = 3.5 , text{radians}$$

Step 2: Use the chord length formula to find displacement:

Displacement=2rsin(θ/2​)
=2×4×sin(3.5/2​)=8×sin(1.75)
sin(1.75radians)≈0.983
$$\text{Displacement}\approx 8\times 0.983\approx 7.864\text{meters}$$