Explanation

According to Einstein, increasing the brightness of a beam of light without changing its color will increase the number of photons. 

Einstein's theory of light posits that light consists of discrete particles called photons.

Brightness is related to the number of photons present in a given area over a specific time.

When you increase the brightness of a light beam, you are essentially adding more photons to that beam,

While keeping the energy of each photon the same (which is related to its frequency and color).

Explanation

The first organic compound prepared in the laboratory was Urea. 

German chemist Friedrich Wöhler synthesized urea from ammonium cyanate in 1828,

Marking a significant milestone in organic chemistry. 

Explanation

 If the temperature of the source of heat increases, the efficiency of a Carnot engine will increase.

The efficiency of a Carnot engine is directly related to the temperature difference between the hot and cold reservoirs.

A higher source temperature leads to a greater temperature difference and thus, a higher efficiency. 

Explanation

Sound waves diffract (bend) around corners, allowing us to hear them,

While light waves do not diffract as much, making it impossible to see around corners.

Diffraction is the bending of waves around obstacles or through openings.

Sound waves have longer wavelengths than light waves, which makes diffraction more noticeable for sound.

Polarization is a property of transverse waves, and while light waves can be polarized, sound waves cannot.

Dispersion is the separation of waves into different frequencies,

And while it can occur with light, it's not why we can hear around corners. 

Explanation

Immunization against hepatitis B also protects against hepatitis D (HDV) infection.

Hepatitis D virus can only infect individuals who are already infected with hepatitis B.

Therefore, vaccination against hepatitis B also prevents hepatitis D infection, as the hepatitis B surface antigen is necessary for the HDV to replicate.

Explanation

The transistor is a semiconductor device with at least three terminals.

These terminals are typically referred to as the :

• Emitter
• Base
• Collector

They allow the transistor to control the flow of electrical signals and power. 

Explanation

The most stable hydrocarbon among the given options is trans-2-butene. 

Stability in alkenes:

• The stability of alkenes is primarily determined by the degree of substitution at the double bond.
• More substituted alkenes are generally more stable. 

Trans vs. Cis Isomers:

• In the case of 2-butene, the trans isomer is more stable than the cis isomer.
• This is because in the trans configuration, the alkyl groups on either side of the double bond are oriented away from each other, minimizing steric hindrance.
• In the cis configuration, the alkyl groups are on the same side, leading to steric repulsion and less stability. 

Explanation

Ethylene glycol (HOCH2CH2OH) is a 1,2-diol, and both periodic acid (HIO4) and lead tetraacetate (Pb(OAc)4)

They are strong oxidizing agents capable of cleaving the carbon-carbon bond between the adjacent hydroxyl groups in a glycol

Resulting in the formation of carboxylic acids. In the case of ethylene glycol, this would yield oxalic acid (HOOC-COOH). 

Explanation

Total distance = Length of train + Length of bridge = 100 m + 200 m = 300 m  

Speed = 15 m/s  

Time = Distance / Speed = 300 / 15 = 20 seconds

Explanation

 The statement correct for all viruses but not for all bacteria and fungi is They have a Nucleus Containing DNA or RNA.

Viruses:

Viruses are obligate intracellular parasites, meaning they lack a nucleus and replicate inside the host cell's nucleus.

They have genetic material (DNA or RNA) but not housed within a nucleus. 

Bacteria and Fungi:

Bacteria and fungi are cells, and while some bacteria are prokaryotic (lacking a nucleus), they still have their own DNA or RNA contained within a nucleus-like structure.

Some fungi have a cell wall made of cellulose, but not all.