Explanation

• Sodium carbonate forms a basic solution in water because it is a salt of a strong base (NaOH) and a weak acid (H₂CO₃).
• Carbonate ions react with water to produce hydroxide ions (OH⁻), increasing the pH above 7.

Last verified on 27-10-2026

Explanation

• Chromium has atomic number 24, so it has 24 electrons.
• Its most stable electronic configuration is [Ar] 3d⁵ 4s¹.
• The half-filled 3d subshell (3d⁵) provides extra stability.

Last verified on 27-10-2026

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