Questions

Q:

Hydrogen atom is excited from ground state to another state with principal quantum number equal to 4. Then the number of spectral lines in the emission spectra will be

A) 2 B) 6
C) 5 D) 3
 
Answer & Explanation Answer: B) 6

Explanation:

Number of spectral lines from a state n to ground state is

 

                   n(n-1)/2 = 6

Report Error

View Answer Report Error Discuss

Filed Under: Physics
Exam Prep: AIEEE

11 5986
Q:

When a steel ball is placed on the surface of mercury, it does not sink because

A) of the surface tension of mercury B) mercury is a semisolid
C) of the high viscosity of mercury D) the density of mercury is greater than that of steel
 
Answer & Explanation Answer: D) the density of mercury is greater than that of steel

Explanation:

A solid sinks in a liquid if its density is greater than that of the liquid. if less, it floats

Report Error

View Answer Report Error Discuss

Filed Under: Physics

8 5984
Q:

On which day ' National Science Day ' is celebrated in India ?

A) February 23 B) February 25
C) February 26 D) February 28
 
Answer & Explanation Answer: D) February 28

Explanation:

National Science Day is celebrated in India on 28 February each year to mark the discovery of the Raman effect by Indian physicist Sir Chandrashekhara Venkata Raman on 28 February 1928.

Report Error

View Answer Report Error Discuss

Filed Under: Physics
Exam Prep: Bank Exams , CAT
Job Role: Bank Clerk

23 5978
Q:

The book “Indira Gandhi – A life in Nature”, authored by _____________.

A) Jairam Ramesh B) Anand Sharma
C) Ghulam Nabi Azad D) Chetan Bhagath
 
Answer & Explanation Answer: A) Jairam Ramesh

Explanation:

The book “Indira Gandhi – A life in Nature”, was launched by Congress president Sonia Gandhi at the Indira Gandhi Memorial in the presence of former ministers, bureaucrats and environmentalists who worked closely with her to frame some of country’s landmarks wildlife and environment laws. Renowned mountaineer Capt Manmohan Singh Kohli recalled how Gandhi once told him “please call me as a daughter of the mountains”. The book has been written by former Union minister Jairam Ramesh and it has been published by Simon & Schuster.

Report Error

View Answer Report Error Discuss

Filed Under: Books and Authors
Exam Prep: Bank Exams
Job Role: Bank PO

11 5974
Q:

The water readily available to plants for absorption by roots is

A) Gravitational water B) Rain water
C) Hygroscopic water D) Capillary water
 
Answer & Explanation Answer: D) Capillary water

Explanation:
Report Error

View Answer Report Error Discuss

Filed Under: Biology
Exam Prep: AIEEE , Bank Exams

20 5972
Q:

What Asks But Never Answers?

A) Teacher B) Telephone
C) Letter D) Owl
 
Answer & Explanation Answer: D) Owl

Explanation:

An owl.

"What noise does an owl make?

The sound an Owl makes, it sounds like, "Who?" to our ears.

They sounds entire lives asking the same question, but they'll never give any answers.

Report Error

View Answer Report Error Discuss

Filed Under: Word Puzzles
Exam Prep: AIEEE , Bank Exams , CAT , GATE
Job Role: Analyst , Bank Clerk , Bank PO

14 5969
Q:

The reactivity of an atom arises from 

A) the existence of unpaired electrons in the valence shell B) the energy differences between the electron shells
C) the sum of the potential energies of all the electron shells D) the average distance of the outermost electron shell from the nucleus
 
Answer & Explanation Answer: A) the existence of unpaired electrons in the valence shell

Explanation:

When atoms react they do so in order to reach the lowest energy, which is the most stable. The electrons orbitals will overlap in the way that reduces the energy the most. Orbitals of similar energy will produce the greatest stabilisation.The answer you gave isn't the whole story, it depends what species is reacting with what. The effective nuclear charge on the atom will affect the energy of the valance electrons.

 

Hence, the reactivity of an atom arises from the existence of unpaired electrons in the valence shell.

Report Error

View Answer Report Error Discuss

Filed Under: Chemistry
Exam Prep: AIEEE , Bank Exams , GATE
Job Role: Analyst , Bank Clerk

4 5967
Q:

Water kept in an earthen pot is less cool on rainy days than in summer because during the rainy days 

A) the pores in the pot are closed B) rain water stops oozing out from the pores
C) the water that oozes out does not evaporate quickely because of the large percent age of moisture in the air D) surface of the pot becomes damp
 
Answer & Explanation Answer: C) the water that oozes out does not evaporate quickely because of the large percent age of moisture in the air

Explanation:

To evaporate the water that oozes out, heat is required. Part of this heat is taken from the water inside which therefore become cool. Therefore (C) is correct. Here evaporation is less, so cooling too is less.

Report Error

View Answer Report Error Discuss

Filed Under: Physics

11 5967