Explanation

• In semiconductors, as the temperature increases, the conductivity increases.
• This is because heat energy excites more electrons into the conduction band, allowing them to flow more freely and increasing the conductivity.
• This is in contrast to metals, where conductivity typically decreases with increasing temperature.

Explanation

• The resistance of a filament lamp increases at higher voltages.
• The increase in voltage leads to an increase in current, which heats up the filament and increases the resistance.
• The increased temperature causes the atoms in the filament to vibrate more, making it more difficult for electrons to pass through and increasing the resistance.

Explanation

Neat means صاف ستھرا

Dapper means صاف ستھرا

Explanation

• Chlorofluorocarbons (CFCs) are not flammable and toxic.
• They are actually non-flammable and non-toxic, but harmful to the environment due to their role in ozone depletion and climate change.

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

• Triethylamine (N(CH₂CH₃)₃) is a tertiary amine, which is a type of amine that has three organic groups attached to the nitrogen atom.
• In this case, the three ethyl groups (CH₂CH₃) are attached to the nitrogen atom.

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

• Covalent network crystals, also known as giant covalent structures, are solids in which each atom is covalently bonded to its neighbors, forming a continuous network of chemical bonds.
• Examples include diamond, graphite, and silicon carbide.
• These materials have very high melting points due to the strong covalent bonds that hold them together.

Explanation

Month of Sundays means a very long time ago.

Month of Sundays بہت عرصہ پہلے

AGM 07.5.23

Explanation

Gun powder is a mixture of sulphur, charcoal and potassium nitrate (KNO3).