Explanation

• The electronic configuration 4d¹⁰ 5s² 5p⁵ belongs to iodine (I), which is a halogen with seven valence electrons.
• Iodine can gain or lose electrons during chemical reactions, so it participates in oxidation-reduction (redox) reactions.
• In a redox reaction, oxidation and reduction occur together through the transfer of electrons or changes in oxidation states.

Last verified on 27-10-2026

Explanation

• Racing cars are made more stable by lowering their centre of gravity, which reduces the tendency to topple while turning.
• A lower centre of gravity helps the car maintain balance when experiencing outward effects during sharp turns.
• Racing cars also use wide tyres and carefully designed suspension systems to improve grip and stability.

Last verified on 27-10-2026

Explanation

Explanation

• A couple consists of two equal and opposite parallel forces acting along different lines of action.
• The resultant force of a couple is zero, but it produces a turning effect called torque or moment of force.
• The torque of a couple is calculated by τ=F×d, where F is the magnitude of either force and d is the perpendicular distance between their lines of action.
• Turning a steering wheel with both hands is a common example of a couple.

Last verified on 26-10-2026

Explanation

• Frequency (f) = number of vibrations per second
• Time period (T) = time for one vibration
• Relation: T = 1 / f
• The time period is the time required to complete one full oscillation or cycle.

Last verified on 26-10-2026

Explanation

• The SI unit of capacitance is the farad (F).
• Capacitance is the ability of a capacitor to store electric charge.
• One farad equals one coulomb per volt (1 F = 1 C/V).

Last verified on 26-10-2026

Explanation

Given:

Angle = 30°

Horizontal component Fx = 20 N

Formula: Fx = F x cos(theta)

So, F = Fx / cos(theta)

F = 20 / cos(30°)

F = 20 / 0.866

F = 23.09 N

F = 23.1 N

Last verified on 26-10-2026

Explanation

• A transformer is an electrical device used to increase or decrease alternating voltage through electromagnetic induction.
• A step-up transformer increases voltage and decreases current.
• While a step-down transformer decreases voltage and increases current, ideally keeping power approximately constant.

Last verified on 26-10-2026

Explanation

• The universal gravitational constant is represented by G.
• Its accepted value is approximately 6.674 × 10⁻¹¹ N m² kg⁻².
• It is used in Newton’s law of universal gravitation to calculate the gravitational force between two objects.

Last verified on 26-10-2026

Explanation

• Starlight passes through Earth’s atmosphere.
• Different air layers have different densities and temperatures.
• Light is repeatedly refracted (bent).
• This causes the star’s brightness to appear to change rapidly.
• This apparent change is called twinkling (scintillation).

Last verified on 26-10-2026