Explanation

• The SI unit of electrical resistance is Ohm (Ω).
• It measures how much a material opposes the flow of electric current.
• Higher resistance means less current flows.
• It is defined by V = IR (Ohm’s Law).
• 1 Ohm = 1 Volt per Ampere.

Last verified on 10-06-2026

Explanation

When white light passes through a prism, it splits into 7 colors, forming a spectrum known as a rainbow:

1. Red
2. Orange
3. Yellow
4. Green
5. Blue
6. Indigo
7. Violet

The separation of visible light into its different colours is known as dispersion.

Last verified on 08-06-2026

Explanation

• The SI unit of electric current is Ampere (A).
• Electric current measures the flow of electric charge.
• Defined using the elementary charge (e = 1.602176634 × 10⁻¹⁹ C).
• Named after: André-Marie Ampère (scientist).
• 1 Ampere = 1 Coulomb per second (1 A = 1 C/s).

Last verified on 08-06-2026

Explanation

• Pressure in gases is due to the collision of gas molecules with the walls of the container.
• Gas molecules are in constant random motion.
• They continuously strike the container walls.
• These collisions create force per unit area (pressure).
• More collisions mean higher pressure.

Last verified on 08-06-2026

Explanation

• Neurons are the basic structural and functional units of the nervous system.
• They are specialized nerve cells.
• They transmit electrical and chemical signals.
• They control communication in the body.
• Brain, spinal cord, and nerves are made up of neurons.

Last verified on 08-06-2026

Explanation

• Short-sightedness is called Myopia.
• It is corrected by a concave lens.
• This lens is thin in the center and thick at edges.
• It helps light focus on the retina correctly.
• Without correction, distant objects look blurred.

Additional information:

• Long-sightedness is called Hypermetropia.
• It is corrected by a convex lens.
• This lens is thick in the center and thin at edges.
• It helps light focus on the retina properly.
• Without correction, near objects look blurred.

Last verified on 07-06-2026

Explanation

• A barometer measures atmospheric (air) pressure.
• It helps in weather forecasting, detecting storms, and studying climate changes.
• Two common types of barometers: mercury barometer and aneroid barometer.

Last verified on 13-03-2026

Explanation

• Violet light has the smallest wavelength, approximately 380-450 nanometers (nm).
• While red light has the longest wavelength, approximately 620-750 nanometers (nm).
• The order of colors in the spectrum, from longest to shortest wavelength, is: Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROYGBIV).

Last verified on 01-04-2026

Explanation

• Citric acid is a natural preservative found in many fruits, particularly in citrus fruits like lemons, oranges, and grapefruits.
• It's responsible for their sour taste and is also used as a food additive.
• Other fruits like mangoes, grapes, and strawberries also contain citric acid, although in smaller amounts.
• The presence of citric acid gives these fruits their characteristic sour taste.

Last verified on 16-03-2026

Explanation

• When light is focused in front of the retina, it creates a blurred image, indicating nearsightedness (myopia).
• This occurs because the eyeball is too long or the cornea is too steep.
• It causing light to focus before reaching the retina.

Last verified on 16-03-2026