Question Discussion & Solution

Ammeter is an instrument used to measure Current.

Similarly, Hygrometer is an instrument used to measure Humidity

The correct answer is 8 minutes.

• It takes 8 minutes to reach the earth.

Key Points

• Light is a form of energy which is propagated as electromagnetic waves.
• In the spectrum of electromagnetic waves, it lies between the ultra-violet and infra-red region and has a wavelength between 3900 Å to 7800 Å.
• light behaves as wave and particle both. 
• Speed of light is maximum in vacuum and air (3×10⁸ m/s).
• It is a transverse wave.
• It takes 8 min 19 s to reach on the earth from the sun.
• The light reflected from the moon takes 1.28 s  to reach earth.

Additional Information

• Electromagnetic waves are transverse, hence light is a transverse wave.
• Wave nature of light explains rectilinear propagation, reflection, refraction, interference, diffraction and polarization of light. 
• Refractive Index of a medium is defined as the ratio of the speed of light in a vacuum to the speed of light in the medium. 
• Light is measured with two main alternative sets of units: radiometry consists of measurements of light power at all wavelengths, while photometry measures light with a wavelength.

The correct answer is Copper.

Key Points

• Conductor of electricity
  • In physics and electrical engineering, a conductor is an object or type of material that allows the flow of charge in one or more directions.
  • Materials made of metal are common electrical conductors. 
  • Copper is considered to be a conductor because it conducts the electron current or flow of electrons fairly easily. Most metals are considered to be good conductors of electrical current. Copper is just one of the more popular materials that are used for conductors. Hence, Option 4 is correct.
  • If you have to define the meaning of electrical conductors in the simplest way, they are materials that allow electricity to flow through them easily.
  • If we compare two types of material and the first one allows better flow of electricity through it, then that material is said to be a good conductor of electricity.
  • An electrical conductor allows the electric charges to easily flow through them. The property of conductors to conduct electricity is called conductivity.
  • Such materials offer less opposition or resistance to the flow of charges.
  • Conducting materials allow easy charge transfer because of the free movement of electrons through them.

Additional Information

• • Some examples of conductors of electricity are
    • Copper
    • Aluminum
    • Silver
    • Gold
    • Graphite
    • Platinum
    • Water
    • People

Given pair is profession: work place

Teacher work in school

Similarly, Astronomer works in Observatory.

For other options farmer works in field, Chef works in kitchen and Tailor works in Boutique no such combination is given except Astronomer who works in observatory.

The correct answer is 1878.

• Vernacular press act was passed in 1878.

Key Points

• The Vernacular Press Act, 1878 came to be known as the Gagging Act as it discriminated between the English and the Vernacular Press.
• Vernacular Press Act, in British India, the law enacted in 1878 to curtail the freedom of the Indian-language (i.e., non-English) press.
• Lord Lytton passed the Vernacular Press Act 1878.
•  He also passed the Arms Act 1878 that prohibited Indians from carrying weapons of any kind without licenses.

Additional Information

• Indian National Awakening was the prime motive of vernacular newspapers.
• The law was repealed in 1881 by Lytton’s successor, Lord Ripon.
• Provisions of the Vernacular Press Act, 1878 include :
  • The publisher had to deposit the security and in case of infringement of the provision of the act the security could be forfeited.
  • If the offence reoccurred, the press equipment could be seized.