Explanation

If the maximum value of the principal quantum number (n) for an atom is 4, the total number of electrons in that atom is 32.

This is because the maximum number of electrons in a shell is given by 2n², and for n=4, this calculation results in 2 * 4² = 32. 

Explanation

 One gram atom of any element refers to one mole of its atoms.

- The molar mass of chlorine (Cl) is approximately 35.5 g, so:

  - One gram atom of chlorine = 1 mole of Cl atoms = 35.5 g, not 71 g (which is for Cl₂ molecules).

Explanation

The atomic mass of sodium is 23 g/mol.  

- This means 1 mole (6.022 × 10²³ atoms) of sodium weighs 23 grams.  

- So, the mass of one atom of sodium is:

= 23 g / Nₐ  

= 23 / (6.022 × 10²³) grams

So the correct option is: 23 / Nₐ g.

Explanation

The magnetic force on a moving charge is given by the cross product of velocity and magnetic field.

Its direction is perpendicular to both v and B, following the right-hand rule.

Explanation

Resistivity (ρ) is a material property that measures how strongly a material opposes electric current.

For copper, the standard resistivity at 20°C is approximately 1.68 × 10⁻⁸ Ω·m.

Explanation

In a transistor, the emitter-base junction is forward-biased. 

For a transistor to function properly as an amplifier, the emitter-base junction needs to be forward-biased, allowing current to flow from the emitter to the base. 

Explanation

If two metallic conductors have the same resistivity, they can be differentiated based on their temperature coefficient. 

The temperature coefficient of resistivity indicates how much the resistivity of a material changes with a temperature change.

Materials with the same resistivity can have different temperature coefficients, meaning their resistance will change differently as temperature changes. 

Explanation

The negative gradient of electric potential is called Electric field intensity. 

Gradient:

In general, a gradient represents the rate of change of a function for a given variable.

In the context of electric fields, the gradient of electric potential indicates how quickly the potential changes as you move in a particular direction. 

Negative gradient:

The "negative" part signifies that the electric field points in the direction of decreasing potential. 

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