Explanation

• A lever is a stiff bar that rests on a support called a fulcrum, which lifts or moves loads.
• The fulcrum is the point where the lever pivots, and it can be used to change the direction of a force or to gain a mechanical advantage, making it easier to lift or move heavy loads.
• Examples: Hammer, crow bar, a pair of pilers and seesaw.

Explanation

• For a vector field to be solenoidal, its divergence must be zero. The divergence of a vector field A = (x + 3y)i + (y - 2z)j + (x + mz)k is given by ∇ ⋅ A = ∂(x + 3y)/∂x + ∂(y - 2z)/∂y + ∂(x + mz)/∂z.
• Calculating the divergence:
  
• ∇ ⋅ A = 1 + 1 + m
• For the field to be solenoidal (∇ ⋅ A = 0), m must be -2.

Explanation

 A ray of light represents the direction of propagation of the wave.

A wavefront is a surface over which the phase of the wave is constant.

Rays are always perpendicular to the wavefronts.

Explanation

The average daily human energy intake is roughly 2000-2500 kilocalories.

One liter of petrol contains approximately 34.2 Megajoules (MJ) of energy, equivalent to roughly 8342 kilocalories.

Therefore, 1/4 liter of petrol has about 8.55 MJ of energy, which is closer to the daily human energy needs than the other options. 

Explanation

Explanation

Explanation

A Circuitry is a path in an electronic circuit.  

In electronics, a circuit is a complete circular path that electricity flows through.

A simple circuit consists of a current source, conductors and a load.

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Explanation

The meaning of the steady current is that the current is uniform all over the conductor.

Therefore, it will be constant throughout the length of the conductor.

Hence, current (i) flowing in a conductor is independent of the cross sectional area of the conductor.

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Explanation

The ammeter is used to indicate the amount of current flowing to and from the battery.

It measures the electric current in amperes to monitor battery usage and health.

Explanation

A converging lens (also known as a convex lens) refracts parallel rays of light and converges them at a single point, called the focal point.