Tag: evs

Questions Related to evs

An atom of an element loses two electrons to form an ion. The quantum numbers of the electrons lost are $n = 4 :and :l = 0$. If another atom of the same element loses one more electron to form an ion, the quantum numbers (Principle and Azimuthal) of this electron lost are ________.

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. 1,2

  2. 3,2

  3. 3,4

  4. 4,5

Show answer
Correct Option: B
Explanation:

Quantum number $n = 4,:l = 0$ corresponds to 4s electrons. When two 4s electrons are lost, a dipositive ion is formed. The configuration of the element could be $3s^23p^64s^2 :or :3s^23p^63d^{1-10} 4s^2$. Since the atom of the same element can lose one more electron, it should be the 'd' block element. 


Iron is the element showing +2 and +3 oxidation states, the configuration could be $3s^23p^63d^64s^2$. The $3^{rd}$ electron lost has quantum numbers $n = 3$, $ l=2$.$Fe^{+3}$  is smaller than $Fe^{+2}$ ion. This is because effective nuclear force of attraction in $Fe^{+3}$  is more than that in $Fe^{+2}$.

Assuming that the number of maximum permissible shells is 5, elements would be there in the periodic table is:

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. 52

  2. 54

  3. 55

  4. 51

Show answer
Correct Option: B
Explanation:

According to Aufbau principle the order of filling of orbitals is:
$1s\ 2s\ 2p\ 3s\ 3p\ 4s\ 3d\ 4p\ 5s\ 4d\ 5p\ 6s\ 4f\ 5d\ 6p$
For maximum shell of 5, electrons will be filled upto 5p orbital as (each period)
$(1s^2)(2s^22p^6)(3s^23p^6)(4s^23d^{ 10 }4p^6)(5s^24d^{ 10 }5p^6)$
$2+8+8+18+18=54$
Therefore maximum number of atoms would be 54.
option B is correct.

Temperate forests occur in India in

evs forests and life conservation of forest and wildlife wildlife forest - the dwelling place of animals forest and its importance deforestation and conservation

  1. Indo-Gangetic plains

  2. Himalayas

  3. Eastern India

  4. Southern Peninsula

Show answer
Correct Option: B

The branch of science that deals with the development of
forest and utilization of forest product is

evs forests and life conservation of forest and wildlife wildlife forest - the dwelling place of animals forest and its importance deforestation and conservation

  1. Horticulture

  2. Sericulture

  3. Silviculture

  4. Pharmocognosy

Show answer
Correct Option: C
Explanation:

Silviculture is the process of controlling the growth, composition, health, and quality of the forests to satisfy people's diverse needs and values.

So the correct option is C

Percentage of forests in our country ____________.

evs forests and life conservation of forest and wildlife wildlife forest - the dwelling place of animals forest and its importance deforestation and conservation

  1. $9\%$

  2. $19\%$

  3. $29\%$

  4. $39\%$

Show answer
Correct Option: A

Scared groves are specially useful in

evs forest : our life conservation of forest and wildlife wildlife forest - the dwelling place of animals deforestation and conservation

  1. generating environmental awareness

  2. preventing soll erosion

  3. year-round flow of water in rivers

  4. conserving rare and threatened species

Show answer
Correct Option: D
Explanation:

Sacred groves are one of the methods of conserving rare and threatened species as local people worship and not allow the killing of animals and cutting of trees in such areas like Khasi and Jaintia Hills in Meghalaya, Aravalli Hills in Rajasthan etc.

So the correct option is 'conserving rare and threatened species'

Which weedicide can defoliate the complete forest?

evs forests and life conservation of forest and wildlife wildlife forest - the dwelling place of animals forest and its importance deforestation and conservation

  1. $2, 4-D$

  2. $MH$

  3. $AMO-1618$

  4. $ABA$

Show answer
Correct Option: A

The heart is slightly tilted towards the 

evs transportation in animal and plants circulatory system and organs blood and blood vessels transportation in living organisms blood pressure circulatory system blood circulatory system

  1. Right side

  2. Not tilted at all

  3. Left side

  4. Upper side

Show answer
Correct Option: C
Explanation:

The human circulatory system consists of a muscular four-chambered heart, a network of closed branching blood vessels and blood, the fluid which is circulated. The heart is mesodermal in origin. It is situated in the thoracic cavity, in between the two lungs. The heart is slightly tilted towards the left side because the right lung is larger than the left lung. This condition provides the heart with enough space to function properly and pump blood efficiently to different parts of the body.

So, the correct answer is 'Left side'.

An example of water-borne disease is 

evs who will do this? personal and public cleanliness basics of water pollution sewage treatment

  1. Scabies

  2. Influenza

  3. Trachoma

  4. Typhoid

Show answer
Correct Option: D

The process of obtaining salt from sea water involves:

evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

  1. evaporation

  2. condensation

  3. sublimation

  4. none of these

Show answer
Correct Option: A
Explanation:
The process of obtaining salt from sea water involves the process evaporation is used an a large scale to obtain common salt from sea water. Sea water is trapped in shallow lakes and allowed to stand there. The heat of sun gradually evaporates water in the shallow lakes and common salt is left behind as a solid. Sea water has many salts dissolved in it.