Electron | MCQs

Explanation

At constant temperature, the resistance (R) of a conductor is inversely related to its cross-sectional area (A). This is expressed by the formula: R = ρ × L / A

where:

• R is the resistance
• ρ (rho) is the resistivity of the material
• L is the length of the conductor
• A is the cross-sectional area

As the cross-sectional area (A) increases, the resistance (R) decreases, and vice versa. This is why thicker wires have lower resistance than thinner wires.

Explanation

• A microphone converts sound waves into electrical signals, which are analogue in nature.
• The voltage signal generated by a microphone is a continuous signal that varies in amplitude and frequency in response to the sound waves.
• This signal is an analogue representation of the sound wave, and it is not digital.

Explanation

The phenomenon where light of suitable frequency falling on a metal surface ejects electrons is called the "photoelectric effect."

Explanation

Einstein’s photoelectric equation is "hv = hvo + (1/2 mv^2) max", where:

• hv is the energy of the incident photon
• h is Planck's constant
• vo is the threshold frequency
• m is the mass of the emitted photoelectron
• max is the maximum kinetic energy of the emitted photoelectron.

Explanation

A neutral sodium atom (Na) has 11 electrons.

Na⁺ loses 1 electron, so it has 10 electrons.

Explanation

Explanation

The quantum number that describes the shape of an electron in an atom is the azimuthal quantum number (l). 

Explanation

In Bohr's model, electrons occupy specific energy levels around the nucleus.

When an electron moves from a lower energy level to a higher energy level, it absorbs energy

Conversely, when an electron moves from a higher energy level to a lower energy level, it emits energy.

This energy is emitted as a photon of light with a specific wavelength, corresponding to a specific frequency. 

Explanation

When the 6d orbital is completely filled, the next electron enters the 7p orbital.

This is based on the Aufbau principle, which dictates that electrons first occupy the lowest energy levels available.

After the 6d orbitals (which can hold up to 10 electrons) are filled, 

The 7p orbitals (which can hold up to 6 electrons) become the next lowest energy

Explanation

Across the periods of the periodic table, the shielding effect remains relatively constant.

This is because the number of inner shell electrons, which are responsible for shielding, does not change as you move across a period.