Explanation

The velocity of sound is calculated using the formula:

Velocity=Frequency×Wavelength

Given:

Frequency = 300 Hz

Wavelength = 4 ft

Velocity=300×4=1200 ft/sec

Explanation

Reverberation time is mainly influenced by:

• The volume of the room

• The absorptive properties of surfaces

• The number of sound-absorbing objects or people

While absorption can vary slightly with frequency, the frequency itself is not a primary controlling factor of reverberation time.

Explanation

In longitudinal waves, the particles of the medium (air molecules, in this case) vibrate back and forth in the same direction as the wave is moving.

This is how sound propagates through gases like air.

Laplace also corrected Newton's theory by including the effect of adiabatic compression, improving the accuracy of the speed of sound calculation in air.

Explanation

A mosquito produces a high-frequency sound, while a lion produces a low-frequency roar.

The difference in frequency is what makes their sounds so distinct to our ears.

Higher frequencies sound more like buzzing or whines, while lower frequencies sound deeper and more powerful.

Explanation

A hydrophone is an instrument designed to detect and record sound underwater.

It's essentially the underwater equivalent of a microphone and is commonly used in:

• Marine biology (e.g., studying whale calls or dolphin clicks)

• Submarine and naval operations (e.g., detecting other submarines or ships)

• Environmental monitoring (e.g., measuring underwater noise pollution)

• Underwater research (e.g., studying seismic activity or underwater volcanic eruptions)

Explanation

Muhammad bin Qasim controlled the Indus Valley as far north as the city of Multan.

He defeated Raja Dahir, the last Hindu ruler of Sindh

From 708 to 711, Muhammad ibn al-Qasim led the Sindh conquest

Explanation

Jai Singh, a son of Raja Dahir, did embrace Islam.

He was later killed by Junaid bin Abdur Rahman. 

Raja Dahir was the last Hindu ruler of Sindh in present-day Pakistan.

In 712 CE his kingdom was invaded by the Umayyad Caliphate led by Muhammad bin Qasim

where Dahir died while defending his kingdom.

Aror was the capital of King Dahir

******

راجہ داہر موجودہ پاکستان میں سندھ کے آخری ہندو حکمران تھے۔ 712عیسوی میں اس کی سلطنت پر اموی خلافت نے حملہ کیا جس کی قیادت محمد بن قاسم کر رہے تھے۔

جہاں داہر اپنی سلطنت کا دفاع کرتے ہوئے مر گیا۔

Explanation

Hakim Shaibani was a key lieutenant under Muhammad bin Qasim during the conquest of Sindh in the early 8th century.

 Muhammad bin Qasim sent his trusted commander Abu Hakim Shaibani toward Kanauj 

Additional information 

Muhammad ibn Qasim led the Muslim conquest of Sindh

From Raja Dahir in the battle of Aror.

He was the first Muslim to have successfully captured Hindu territories

And initiated the early Islamic India in 712 AD.

Explanation

The Thal Desert is situated in the Bhakkar District of Punjab.

It is located between the Jhelum and Sindh rivers near the Pothohar PlateauIts.

The Length of the Thal desert is 190 miles.

It is called the Friendly Desert and Great Indian Desert.

It is the largest and the National Desert of Pakistan.

It is the 16th largest desert on the planet

15% located in Pakistan.

85% located in India

Famous for: Sand and Coal 

Additional information:

Pakistan hosts five major deserts which are historic forests.

1.       Cholistan (Bahawalpur, Punjab)

2.       Thal (Bkhar district of Punjab)

3.       Katpana desert (Sakardu)

4.       Kharan desert (Balochistan)

5.       Thar desert (Sindh)

In KPK there is no desert

The northern area of Pakistan is known as the “Deserts Free Area”.

Explanation

The first-ever general elections were held on 7th December 1970.

Yahya Khan issued a Legal Framework Order for the first general elections.

300 of the 313 seats in the National Assembly

of which 162 were in East Pakistan and 138 in West Pakistan.

A further thirteen seats were reserved for women (seven of which were in East Pakistan and six of which were in West Pakistan)