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An isotropic solid has the same value of physical properties when measured along different directions. Therefore, the given solid, having the same value of refractive index along all directions, is isotropic in nature. Hence, the solid is an amorphous solid. When an amorphous solid is cut with a sharp edged tool, it cuts into two pieces with irregular surfaces.

Potassium sulphate → Ionic solid 

Tin → Metallic solid 

Benzene → Molecular (non-polar) solid

 Urea → Polar molecular solid

 Ammonia → Polar molecular solid

 Water → Hydrogen bonded molecular solid Zinc sulphide → Ionic solid

 Graphite → Covalent or network solid Rubidium → Metallic solid

 Argon → Non-polar molecular solid 

Silicon carbide → Covalent or network solid 

The given properties are the properties of a covalent or network solid. Therefore, the given solid is a covalent or network solid. Examples of such solids include diamond (C) and quartz (SiO₂).

In ionic compounds, electricity is conducted by ions. In solid state, ions are held together by strong electrostatic forces and are not free to move about within the solid. Hence, ionic solids do not conduct electricity in solid state. However, in molten state or in solution form, the ions are free to move and can conduct electricity. 

The significance of a lattice point is that each lattice point represents one constituent particle of a solid which may be an atom, a molecule (group of atom), or an ion. 

Answer : 87.18%

The six parameters that characterise a unit cell are as follows. 

(i) Its dimensions along the three edges, a, b, and c These edges may or may not be equal.

 (ii) Angles between the edges These are the angle α (between edges b and c), β (between edges a and c), and γ (between edges a and b). 

Metallic solids are electrical conductors, malleable, and ductile. 

8 corner × 1/8 atom per unit cell = 1 atom

 There are four body diagonals in a cubic unit cell and each has two body centre atoms.

 So, 4 × 2 = 8 atoms therefore, total number of atoms per unit cell = 1 + 8 = 9.

Hint : (a) Ge is group 14 element and In is group 13 element. Therefore, an electron deficit hole is created. Thus semiconductor is p-type.

 (b) Since B is group 13 element and Si is group 14 element, there will be a free electron, thus, it is n-type semiconductor

Given:

The cost price of the shirt is Rs.1 50 = selling price to gain 20%

Formula Used:

Profit percentage = {(SP – CP)/CP} × 100

Calculation:

SP of shirt = (120 × 150)/100 = 180

Correct option is (1) By electrolysis of warm aqueous barium hydroxide solution using Ni electrodes

High purity (>99.95%) dihydrogen is obtained by electrolysis of warm aqueous barium hydroxide solution
between nickel electrodes.

Given:

The cost price of 40 phones = The selling price of 25 phones

Formula Used:

Profit percentage = {(SP – CP)/CP} × 100

Calculation:

Let CP of 1 phone be Rs. x

CP of 25 phones = Rs. 25x

CP of 40 phones = Rs. 40x

SP of 25 phones = Rs. 40x

Gain percentage = (40x – 25x)/25x × 100 = 60%

Given:

The cost price of 15 fishes = The selling price of 12 fishes

Formula Used:

Profit percentage = {(SP – CP)/CP} × 100

Calculation:

Let CP of 1 fish be RS x

CP of 12 fishes = Rs 12x

CP of 15 fishes = Rs 15x

SP of 12 fishes = Rs 15x

Gain percentage = (15x – 12x)/12x × 100 = 25%

Difference between fixed cost and variable cost.

Average cost is the sum of average fixed cost and average variable cost. 

Hence

ATC (AC) = AFC + AVC 

So, ATC - AVC = AFC

This shows that difference between ATC and AVC is equal to AFC.

AFC is obtained by dividing total fixed cost by output, i.e. AFC=TFC / Q

And total fixed cost (TFC) is constant.

Therefore, with the increase in the level of output, AFC falls.

Thus, the difference between ATC and AVC decreases with increase in output.

No, ATC and AVC cannot be equal at any level of output as gap between them i.e. 

AFC can never be zero because TFC is constant and positive.

Supply- The quantity of a commodity that the producer is willing to sell at a given price during a given period of time is called supply.

Market Supply -The quantity of a commodity which all the sellers in the market wish to sale at a given price and given period of time is called market supply. 

The factors affecting supply or Determinants of supply -

i) Technological changes - Technological advancement in the field of production leads to decrease the cost of production and increases the production and supply of good. The technological progress shifts supply curve to the right and vice versa. 

ii) Price of other goods - With the fall in the price of other goods, supply of good increase. The supply curve shifts to the right and vice versa. 

iii) Change in input price - If the price of factor inputs decreases it decreases the cost of production and increase the production & supply of good. The supply curve shifts to the right and vice versa.

iv) Change in the excise tax rate - If the excise duty decreases, it decreases the production cost and increases the production & supply of good. The supply curve shifts to the right and vice versa. 

Demand - The quantity of a commodity which a consumer wish to purchase at given price and given period of time is called demand.

Market demand- The quantity of a commodity which all the consumers in the market wish to purchase at a given price and given period of time is called market demand.

Determinants of demand- The main determinants of demand for a commodity are as follows

i) Price of the commodity- When the price of a commodity increases the demand for that commodity decreases and vice versa. It means there is inverse relationship between price of commodity and quantity demanded.

ii) Income of the consumer - The income of consumer affects the demand of commodity as follows

The demand for normal goods tends to increase with increase in consumer income and vice-versa. On the other hand, the demand for inferior goods tends to decrease with increase in consumer income and vice-versa.

iii) Taste and preferences- When taste and preferences are in favour of the commodity demand for commodity increases and vice versa.

iv) Future expectation of change in price of good- If it is expected that price of commodity will increase in future ,consumer starts purchasing the commodity more at present. Therefore demand of commodity increases at present and vice versa. 

v) Price of related goods - The related goods are of two types- complementary goods (The goods which are used together) and supplementary good (The goods which are used in place of each other).

In case of complementary goods, demand of a good rises with fall in price of complementary good and vice versa. In case of supplementary (substitute) goods, demand of a good falls with a fall in the price of other substitute goods and vice versa.

The above five factors affect the individual demand. But for market demand some more factors including above are as under -

vi) Government policy - When government increases the tax on a particular commodity, the commodity become costlier, so less number of consumers will purchase the commodity. Hence demand of commodity decline and vice versa.

vii) Population- With increase in population of a country demand for commodity rises. However, if the population is decreasing, then demand will fall.

viii) Climate - If climate of an area is favourable for the consumption of a good then demand for the good will be more and vice versa.

GIVEN:

By selling a TV at Rs. 25000, a dealer suffers a loss of 12%.

CONCEPT:
Basic concept of Profit and Loss.

FORMULA USED:

SP = CP × [1 – loss]/100

SP = CP × [1 + profit]/100

CALCULATION:

Let the cost price of the TV be x.

Now, by selling at Rs. 25000, a loss of 12% is incurred.

Hence,

(1 – 12/100)x = 25000

⇒ x = 25000/0.88

Now, to make a profit of 10%, he should sell it at (1 + 10/100)x

= 110/100 × (25000/0.88)

= Rs. 31250