Questions

Q:

The fundamental particles present in equal numbers in neutral atoms are

A) protons and electrons B) neutrons and electrons
C) protons and neutrons D) protons and positrons
 
Answer & Explanation Answer: A) protons and electrons

Explanation:
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Q:

Which of these molecules are polar? Check all that apply.

A) SO2 B) CH2Cl2
C) PCl3 D) All the above
 
Answer & Explanation Answer: D) All the above

Explanation:

   1) SO2                  2) CH2Cl2                3) PCl3

polar1525846214.jpg image

How to check the given molecules are polar or non polar :

If the electronegativity of the two bonded atoms are different then the bond is polar. Although, some molecules contain polar bonds, the molecule may be non-polar. If the polarity of all the bonds present in the molecule are cancel each other then molecule is non-polar.

 

In the given options,

SO2  is polar because the dipole moments on the O do not cancel.

PCl3  is polar because the P-Cl bonds do not cancel out.

CH2Cl2  polar because the C-Cl bonds do not cancel.

 

Hence, in brief, Polar molecules are molecules with net dipole due to the presence of partial positive and partial negative charge.

For example, water is a polar molecule that has partial positive and partial negative charge on it. CO2 is a non polar compound.

 

Therefore, all the given options SO2, CH2Cl2 and PCl3 are Polar molecules.

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5 9703
Q:

What holds the sides of the DNA ladder together?

A) Polar covalent bonds B) Ionic bonds
C) Metallic bonds D) Covalent bonds
 
Answer & Explanation Answer: D) Covalent bonds

Explanation:

Deoxyribose, which is a pentose, and a phosphate group are the two molecules together form the two sides of the DNA i.e, A sugar (deoxyribose) and a phosphate.

DNA is a double-stranded molecule twisted into a helix (think of a spiral staircase). Each spiraling strand, comprised of a sugar-phosphate backbone and attached bases, is connected to a complementary strand by non-covalent hydrogen bonding between paired bases. The bases are adenine (A), thymine (T), cytosine (C) and guanine (G). A and T are connected by two hydrogen bonds. G and C are connected by three hydrogen bonds.

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16 9703
Q:

What is the main reason the OSI Model was created?

Answer

The OSI Model is used as a reference model.


The primary reason the OSI model was created was so that different networks could inter-operate. Hence, different networks could communicate.

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20 9702
Q:

A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emissions is at 680 nm, the other is at :

A) 518 nm B) 1035 nm
C) 325 nm D) 743 nm
 
Answer & Explanation Answer: D) 743 nm

Explanation:

1λ=1λ1+1λ2

1355=1680+1λ2

1λ2=680-355680×355

λ2=743nm.

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Q:

Age of a Candidate to contest Parliamentary election should not be lesser than

A) 18 years B) 21 years
C) 25 years D) 26 years
 
Answer & Explanation Answer: C) 25 years

Explanation:
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7 9687
Q:

Prophet of New India is

A) Dayanand Saraswathi B) Sri Ramakrishna
C) Swamy Vivekananda D) Raja Ram Mohan Roy
 
Answer & Explanation Answer: B) Sri Ramakrishna

Explanation:

Sri Ramakrishna is called as the Prophet of New India.

Sri Ramakrishna (1836-86) mostly known as Ramakrishna Paramhamsa was a spiritual genius now respected in India and abroad as an outstanding saint of our times. His life and thoughts represents the highest and best of modern Hindu philosophy and practice.

Reverence and admiration for him amongst Bengali elites led to the formation of the Ramakrishna Mission by his chief disciple Swami Vivekananda. His devotees look upon him as an incarnation or Avatara of the formless Supreme Brahman as described in the Vedanta while some devotees see him as an avatara of Vishnu.

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20 9673
Q:

An element which is preserved under water is 

A) sodium B) sulphur
C) red phosphorus D) white phosphorus
 
Answer & Explanation Answer: D) white phosphorus

Explanation:

White phosphorus undergoes spontaneous combustion when exposed to air. In order to prevent this spontaneous ignition, it is preserved under water. 

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27 9667