Explanation

In a vacuum or free space, there are no particles or matter, so:

• Pressure (p) is zero.
• Current density (J) is also zero, since there are no charged particles to carry current.

Therefore, the correct observation is p = 0, J = 0.

Explanation

Gamma rays are the most dangerous because they have the highest energy.

It can penetrate deep into tissues, causing severe damage to cells and DNA.

Explanation

Explanation

Explanation

In a complete cell diagram, a double vertical line (||) represents the salt bridge.

It allows ion flow to maintain electrical neutrality.

Explanation

Explanation

Explanation

Fehling's test and Tollen's test are used for the identification of:

Aldehydes: Both tests are specific for detecting aldehydes, as aldehydes can be oxidized to carboxylic acids, producing a positive result.

Distinctive results:

Fehling's test: Forms a red precipitate of copper(I) oxide with aldehydes.

Tollen's test: Produces a silver mirror with aldehydes.

Explanation

The velocity potential (φ) of an incompressible fluid satisfies Laplace's equation:

∇²φ = 0

This equation represents the conservation of mass for an incompressible fluid.

Explanation

r(cosθ + isinθ)

This is the polar form of a complex number.

where r is the magnitude (or modulus).

θ is the argument (or angle).