Explore topic-wise InterviewSolutions in .

(a). e- 

(b). p+

(c). n

Protons and neutrons are collectively present in the nucleus at the centre while electrons revolve rapidly round the nucleus in fixed circular orbits called energy levels.

Mass of proton is 1837 times the mass of electron.

(c) hydrogen

Electron has relative charge of -1 u whereas neutron has no relative charge. 

Also, electron has relative mass of 1/1840 u and neutron has relative mass of 1 u.

Electron has relative mass of 1/1840 u, proton has 1u and neutron also has 1u. 

Electron has relative charge of -1u, proton has +1u and neutron has 0 relative charge.

(d) All these

Hydrogen has no neutron.

The mass no. of x is 40

The atomic no. of x  is 20

No. of proton is = Z – A = 40 – 20 = 20

No. of electron its (A) = 20

No. of proton is (A) = 20

For ⁴⁰X₂₀

_{Atomic number = 20}

Mass number = 40

Number of electrons = number of protons = atomic number = 20

Number of neutrons = mass number - atomic number = 40 - 20 = 20

Proton has no electron.

_ZX^A where A = Mass Number, X = atom, Z = Atomic number.

Correct option is: D) Velocity of light

D) Velocity of light

Since atomic number of carbon = 6

Therefore, number of proton = 6

Now, Atomic mass = number of proton + number of neutron

Or, Atomic mass or mass number = 6 + 6 = 12 u

Thus, mass number or atomic mass of carbon = 12u

Neutron = 35 - 17 = 18, Electron = Proton = 17.

Since,

Atomic number = 13

Therefore, number of proton = 13

We know that; Atomic mass (Mass number) = Number of protons + Number of neutrons

Therefore,

27 u = 13 + n

Or, n = 27 – 13 = 14

Therefore, number of proton = 13 and number of neutron = 14

Number of Protons 27, Number of Electrons 27, Number of Neutrons 29.

The two chemical properties are: 

(a) The nature of compounds formed by elements with oxygen. 

(b) The nature of compounds formed by elements with hydrogen.

(a) There will be 13 electrons in each atom of the element. Because in a neutral atom, number of protons is equal to the number of electrons. 

(b) Electronic configuration of given element (2, 8, 3) is 

K= 2 

L=8 

M=3

Atomic No. – 18 

Electronic configuration – (2,8,8) 

The special thing about the outermost shell is that it is completely filled with the electrons. The element will be inert in nature.

A) Littoral zone

B) The organisms would be blind

Correct option is (b) Attention; perception; retention

• In hydrilla stomata are absent, leaves are thin, stems are highly flexible. 
• It can grow at low light intensities.
• It is better at absorbing carbon dioxide from the water. 
• It is able to store nutrients for later use. It can tolerate a wide range of water quality conditions, for example, salinity. 
• Hydrilla can propagate sexually and asexually.

D) Galapagos Islands

D) Neither A nor B is possible

Correct option is b. 17

Correct option is C) Opuntia

To protect themselves from extreme hot conditions, animals that live in burrows usually come out during night time only.

Symbiosis is close and often long term interaction between two or more different biological species. Symbiotic relationships include those associations in which one organism lives on another (ecosymbiosis) and where one partner lives inside the other (endosymbiosis).

18 electrons in an atom can have n + l = 6.

C) Alga – Fungus

B) 600 volts

• Electric eel is an electric fish. 
• It is capable of generating power electric shocks of upto 600 volts, when it uses for hunting self defence. 
• It is an apex predator. 
• Despite its name, it is not an eel, but rather a knife fish.

Temperature, pressure, salinity, etc. effect adaptations to marine life.

• Animals which are active during night and sleep during the day are called nocturnals. 
• These creatures generally have highly developed senses of hearing and smell. 
• They have specially adapted eye sight to see well in dark. 
• Animals like bats, emit a high pitched sound which bounses off objects to find prey or protect from predators. 

E.g : Cats, rats, bats, owls, insects like crickets, firefly and cattle fish.

1. The organisms living in this zone are mostly floaten and swimmen. 

2. Animals in this zone usually have shiny bodies reflecting light away to merge with shiny water surface are transparent. 

3. These usually have sharp vision.

Adaptations provide some improvement for better survival.

Yes, all animals living in desert conditions show adaptations.

l represents the sub-shell and L represents shell. 

Kinds of abiotic conditions in mangrove ecosystems are soil, pH, oxygen, nutrients, winds and currents, light, temperature, humidity, tides, salinity.

Elasticity of demand

Ep = \(\frac{ΔQ}{ΔP}\times\frac{P}{Q}\)

In this example,

ΔQ = 10, ΔP = 1, P = 4, Q = 30

Therefore, Ep = \(\frac{10}{1}\times\frac{4}{30}\) = 0.75

Σ d = -2 

When P = 4, q = 50 

When P = 3, q = ?

\(\sum d = \frac{\Delta Q}{\Delta P} \times \frac{P}{q}\)

-2 = \(\frac{\Delta q}{-1} \times \frac{4}{50} = \frac{4 \Delta q}{-50}\)

100 = 4 Δ q 

Δ q = 100/4 =25 

∴ New quantity = q + Δ q 

= 50 + 25 

= 75

The answer is (c) Strong fruit wall

• Managers commission
• Interest on loan of partner’s
• Rent of building in which business runs.

(a) When the capital are fixed:

• Partners capital account,
• Partners current account

(b) When the capitals are fluctuating:

• Partners capital account.

• To remove the problem of ‘limited capital’.
• To remove the risk taking capacity.