Explanation

• Happy means خوش
• Lucky means خوش قسمت

Last updated: 13-09-2026

Explanation

• Ibn al-Haytham presented the theory of reflection and refraction of light.
• He is also known as Alhazen.
• His work, particularly his "Book of Optics", is titled Kitab al-Manazir, written during 1011–1021.
• Born: c. 965 (c. 354 AH) Basra, Buyid Emirate
• Died: c. 1040 (c. 430 AH)[1] (aged around 75) Cairo, Fatimid Caliphate

Last verified on 02-09-2026

Explanation

Very high frequency is the ITU designation for the range of radio frequency electromagnetic waves from 30 to 300 megahertz,

with corresponding wavelengths of ten to one meter.

ND17-7-2023

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

• Mitochondria are called the powerhouse of the cell.
• Because they produce Adenosine Triphosphate (ATP).
• ATP is the energy currency of the cell.
• ATP provides energy for different cellular activities such as movement, growth, and transport.
• Energy is produced through aerobic cellular respiration using oxygen and الغذائی molecules.
• They are found in the cytoplasm of most eukaryotic cells.
• Richard Altmann first described mitochondria in 1890.

Main Parts of a Cell:

1. Cell membrane → Outer protective layer
2. Nucleus → Controls cell activities
3. Cytoplasm → Jelly-like material between membrane and nucleus

Last verified on 09-05-2026

Explanation

• Photosynthesis produces glucose and oxygen.
• Green plants use sunlight, water, and carbon dioxide.
• This process occurs in chloroplasts using chlorophyll.
• Glucose is used as food for energy and growth.
• Oxygen is released as a byproduct into the atmosphere.

Last verified on 10-03-2026

Explanation

• Physical pendulum depends on moment of inertia (I) and distance (d) from pivot to center of mass.
• Time period increases when mass is farther from pivot (larger d).
• Standard formula is T = 2π√(I/Mgd).

Last verified on 05-06-2026

Explanation

• The average distance covered by an alpha particle in air before losing its ionizing power is called its range.
• Alpha particles lose energy continuously while moving through air.
• They stop ionizing after traveling a certain distance.
• This stopping distance is not straight-line path always due to collisions.

Last verified on 05-06-2026

Explanation

• The sentence is in Simple Present Tense: Lion does not eat grass.
• Passive voice structure: Object + is/am/are + not + past participle + by + subject.
• Therefore, “Grass is not eaten by a lion, however hungry he may be.” is correct.

Last verified on 05-06-2026

Explanation

• Battery is a device that converts chemical energy into electrical energy.
• Batteries work by using a galvanic cell.
• It is an electrochemical device made up of two electrodes and an electrolyte solution.

Last verified on 16-03-2026