Explanation

• Reflection is the process by which light rays bounce back from a surface, without being absorbed or transmitted.
• This occurs when light hits a material object, such as a mirror, metal, or water.

Explanation

• Swimmers make their bodies streamlined to reduce friction underwater.
• It allowing them to move more efficiently and quickly through the water.

Explanation

• A wheel with a rod, called an axle, through its center lifts or moves loads.
• Example: Screw driver, handle is wheel and its shaft is axle, a car wheel.

The wheel and axle simple machine is used in many applications, such as:

• Transportation (cars, bicycles, etc.)
• Lifting heavy loads (cranes, winches, etc.)
• Moving objects (wheelbarrows, shopping carts, etc.)

Explanation

For a straight wire, the induced current (I) depends on:

• The speed of movement of the wire (v): The faster the wire moves, the greater the induced current.
• The length of the wire (L): The longer the wire, the greater the induced current.
• The magnitude of the magnetic flux density (B): The stronger the magnetic field, the greater the induced current.

The induced current is given by Faraday's law of induction: I = -BLv

Where:

• I is the induced current
• B is the magnetic flux density
• L is the length of the wire
• v is the speed of movement of the wire

Explanation

Refractive index is both unitless and dimensionless. 

Refractive index is defined as the ratio of the speed of light in a vacuum to the speed of light in a medium.

Since both speeds have the same units (meters per second),

The units cancel out, making refractive index a dimensionless quantity.

It's also unitless because it doesn't have any associated units

Explanation

Step 1: Parallel Combination

C_parallel = C + C = 2C

Step 2: Series with Third Capacitor

1/C_eq = 1/2C + 1/C

= (1/2C) + (2/2C)

= 3/2C

C_eq = 2C/3

Explanation

Water is called the "universal solvent".

Because it dissolves more substances (e.g., salts, sugars, acids) than any other liquid due to its polarity (uneven charge distribution).

Explanation

According to Einstein’s equation E = mc², where c = 3 × 10⁸ m/s (speed of light),

E = 1 × (3 × 10⁸)² = 9 × 10¹⁶ joules.

This shows that 1 kg of mass can be converted into 9 × 10¹⁶ joules of energy.

Explanation

 The direction of a vector in space is typically specified by three angles.

These angles, often referred to as azimuth, elevation, and tilt (or polar/inclination), describe the vector's orientation in 3D space relative to a chosen reference frame. 

Explanation

Back e.m.f (electromotive force) is the voltage opposing the applied voltage, commonly seen in motors and inductive circuits.

When back e.m.f = 0, there is no opposing voltage, so the entire applied voltage appears across the circuit's resistance.

From Ohm's Law:

I=V−back e.m.f​/R

If back e.m.f = 0, then

I=V/R​(maximum possible current)