Explore topic-wise InterviewSolutions in Current Affairs.

Concept used:

Calculation skills trick.

Calculation:

Step - 1

Write down the squares of each of the digits in two digit format i.e. 8² = 64 and 9² = 81

The number obtained after this step is 6481.

Step – 2

Multiply the digits with each other and also with the power 2 i.e. 8 × 9 × 2 = 144

Step – 3

Add the number obtained in step - 1 with the number obtained in step – 2 keeping the unit place empty i.e.

6 4 8 1

1 4 4 _

7 9 2 1

This is our final answer.

Given:

The given number = 85

Concept:

Calculation skills trick

Calculation:

Step - 1

Write down the squares of 5 = 25

Step – 2

Multiply the digits at tens place to its next term i.e. 8 ×(8 + 1) = 72

Step – 3

Write the result to the left side of the result obtained in Step(1) i.e.

7 2 2 5 

This is our final answer.

Concept used:

Calculation skills trick.

Calculation:

Step - 1

Break down the number in such a way that the unit digit is separate and ten’s and hundred’s digit is together i.e. 16 and 4.

Write down the squares of each of the parts in two digit format i.e. 16² = 256 and 4² = 16

The number obtained after this step is 25616.

Step – 2

Multiply the digits with each other and also with the power 2 i.e. 16 × 4 × 2 = 128

Step – 3

Add the number obtained in step - 1 with the number obtained in step – 2 keeping the unit place empty i.e.

2 5 6 1 6

_ 1 2 8 _

2 6 8 9 6

This is our final answer

D. evaporation

A. Mean free path

Concept used:

Calculation skills trick.

Calculation:

Step - 1

Break down the number in such a way that the unit digit is separate and ten’s and hundred’s digit is together i.e. 17 and 7.

Write down the squares of each of the parts in two digit format i.e. 17² = 289 and 7² = 49

The number obtained after this step is 28949.

Step – 2

Multiply the digits with each other and also with the power 2 i.e. 17 × 7 × 2 = 238

Step – 3

Add the number obtained in step - 1 with the number obtained in step – 2 keeping the unit place empty i.e.

2 8 9 4 9

_ 2 3 8 _

3 1 3 2 9

This is our final answer.

A. increases

Concept used:

Calculation skills trick.

Calculation:

Following steps need to be followed:

•  Write the square of 5 i.e. 25 at the extreme right end.
•   Multiply the digit at tens place to it next term. i.e. (6 x 7) = 42
•   Now write the result to the left side of the result obtained in step (1) i.e. 4225 65² = 4225

E. none of the above 

E. stays the same

Given:

The given number = 72

Concept:

Calculation skills trick

Calculation:

Step(1):

Write down the cube of each of the digits in three digit format i.e. 7³ = 343 and 2³ = 8

The number obtained after this step is 343008.

Step(2):

Now multiply all the digit of the given number with themselves i.e. (7 × 2) = 14

Step(3):

Multiply the result obtained in Step(2) by the power 3 i.e. (14 × 3) = 42

Step(4):

Now multiply the result obtained in Step(3) with the given number i.e. (72 × 42) = 3024

Step(5):

Add the number obtained in Step(1) with the number obtained in Step(4) keeping the unit place empty i.e.

3 4 3 0 0 8

_ 3 0 2 4 _

3 7 3 2 4 8

∴ Cube of 72 = 373248

Concept used:

Calculation skills trick.

Calculation:

Following steps need to be followed:

• Write the square of 5 i.e. 25 at the extreme right end.
•   Now multiply the remaining number to its next number. i.e. (14 x 15) = 21
•   Now write the result to the left side of the result obtained in step (1) i.e. 21025 145² = 21025

B. decreases

Concept used:

Calculation skills trick.

Calculation:

Step - 1

Break down the number in such a way that the unit digit is separate and ten’s and hundred’s digit is together i.e. 45 and 6.

Write down the squares of each of the parts in two digit format.

 45²

Right most two digits will be 5² = 25

Left digits are to be found by multiplying the remaining number by its next number i.e. 4 × 5 = 20

So, 45² = 2025 and 6² = 36

The number obtained after this step is 202536.

Step – 2

Multiply the digits with each other and also with the power 2 i.e. 45 × 6 × 2 = 540

Step – 3

Add the number obtained in step - 1 with the number obtained in step – 2 keeping the unit place empty i.e.

2 0 2 5 3 6

_ _ 5 4 0 _

2 0 7 9 3 6

This is our final answer

The Maxwell-Boltzmann equation, which forms the basis of the kinetic theory of gases, defines the distribution of speeds for a gas at a certain temperature. From this distribution function, the most probable speed, the average speed, and the root-mean-square speed can be derived.

Given:

The given number = 58

Concept:

Calculation skills trick

Calculation:

Step(1):

Write down the cube of each of the digits in three digit format i.e. 5³ = 125 and 8³ = 512

The number obtained after this step is 125512.

Step(2):

Now multiply all the digit of the given number with themselves i.e. (5 × 8) = 40

Step(3):

Multiply the result obtained in Step(2) by the power 3 i.e. (40 × 3) = 120

Step(4):

Now multiply the result obtained in Step(3) with the given number i.e. (58 × 120) = 6960

Step(5):

Add the number obtained in Step(1) with the number obtained in Step(4) keeping the unit place empty i.e.

1 2 5 5 1 2

_ 6 9 6 0 _

1 9 5 1 1 2

∴ Cube of 58 = 195112

Concept used:

Calculation skills trick.

Calculation:

Step - 1

Break down the number in such a way that the unit digit is separate and ten’s and hundred’s digit is together i.e. 75 and 9.

Write down the squares of each of the parts in two digit format.

 75²

Right most two digits will be 5² = 25

Left digits are to be found by multiplying the remaining number by its next number i.e. 7 × 8 = 56

So, 75² = 5625 and 9² = 81

The number obtained after this step is 562581.

Step – 2

Multiply the digits with each other and also with the power 2 i.e. 75 × 9 × 2 = 1350

Step – 3

Add the number obtained in step - 1 with the number obtained in step – 2 keeping the unit place empty i.e.

5 6 2 5 8 1

_ 1 3 5 0 _

5 7 6 0 8 1

This is our final answer.

Given:

The given number = 66

Concept:

Calculation skills trick

Calculation:

Step(1):

Write down the cube of each of the digits in three digit format i.e. 6³ = 216 and 6³ = 216

The number obtained after this step is 216216.

Step(2):

Now multiply all the digit of the given number with themselves i.e. (6 × 6) = 36

Step(3):

Multiply the result obtained in Step(2) by the power 3 i.e. (36 × 3) = 108

Step(4):

Now multiply the result obtained in Step(3) with the given number i.e. (66 × 108) = 7128

Step(5):

Add the number obtained in Step(1) with the number obtained in Step(4) keeping the unit place empty i.e.

2 1 6 2 1 6

_ 7 1 2 8 _

2 8 7 4 9 6

∴ Cube of 66 = 287496

(i) Parallel combination

(ii) #There is no division of voltage among the appliances when connected in parallel. The potential difference across each appliance is equal to the supplied voltage.

#The total effective resistance of the circuit can be reduced by connecting electrical appliances in parallel.

(iii)A and D bcoz of high resistance

Concept used:

Calculation skills trick.

Calculation:

Step - 1

Break down the number in such a way that the unit digit is separate and ten’s and hundred’s digit is together i.e. 44 and 4.

Write down the squares of each of the parts in two digit format i.e. 44² = 1936 and 4² = 16

Note: - For 44², same method is used where the number is broken in 4 and 4 (ten's and unit digit)

The number obtained after this step is 193616.

Step – 2

Multiply the digits with each other and also with the power 2 i.e. 44 × 4 × 2 = 352

Step – 3

Add the number obtained in step - 1 with the number obtained in step – 2 keeping the unit place empty i.e.

1 9 3 6 1 6

_ _ 3 5 2 _

1 9 7 1 3 6

This is our final answer.

Concept used:

Calculation skills trick.

Calculation:

Step - 1

Break down the number in such a way that the unit digit is separate and ten’s and hundred’s digit is together i.e. 64 and 8.

Write down the squares of each of the parts in two digit formats i.e. 64² = 4096 and 8² = 64

Note: - For 64², same method is used where the number is broken in 6 and 4 (ten's and unit digit)

The number obtained after this step is 409664.

Step – 2

Multiply the digits with each other and also with the power 2 i.e. 64 × 8 × 2 = 1024

Step – 3

Add the number obtained in step - 1 with the number obtained in step – 2 keeping the unit place empty i.e.

4 0 9 6 6 4

_ 1 0 2 4 _

4 1 9 9 0 4

This is our final answer.

For monohybrid cross, Mendel began with a pair of pea plants with two contrasting traits, i.e., one tall and another dwarf. The cross-pollination of tall and dwarf plants resulted in tall plants. All the hybrid plants were tall. He continued his experiment with self-pollination of F₁ progeny plants.

Given:

The given number = 86

Concept:

Calculation skills trick

Calculation:

Step(1):

Write down the cube of each of the digits in three digit format i.e. 8³ = 512 and 6³ = 216

The number obtained after this step is 512216.

Step(2):

Now multiply all the digit of the given number with themselves i.e. (8 × 6) = 48

Step(3):

Multiply the result obtained in Step(2) by the power 3 i.e. (48 × 3) = 144

Step(4):

Now multiply the result obtained in Step(3) with the given number i.e. (86 × 144) = 12384

Step(5):

Add the number obtained in Step(1) with the number obtained in Step(4) keeping the unit place empty i.e.

5 1 2 2 1 6

1 2 3 8 4 _

6 3 6 0 5 6

∴ Cube of 86 = 636056

Solution:-

Concept used:-

Trick to multiply two numbers between 10 and 20.

Method:-

• Add the unit digit of the smaller number to the larger number.
• Then, multiply the result by 10.
• Now, multiply the unit digits of both the 2-digit numbers.
• Then add both the numbers.

Calculation:-

Step 1 & 2:- (19 + 6) × 10 = 250

Step 3:- 9 × 6 = 54

Step 4:- 250 + 54 = 304

This is our final answer.

Given:

The given number = 37

Concept:

Calculation skills trick

Calculation:

Step(1):

Write down the cube of each of the digits in three digit format i.e. 3³ = 27 and 7³ = 343

The number obtained after this step is 27343.

Step(2):

Now multiply all the digit of the given number with themselves i.e. (3 × 7) = 21

Step(3):

Multiply the result obtained in Step(2) by the power 3 i.e. (21 × 3) = 63

Step(4):

Now multiply the result obtained in Step(3) with the given number i.e. (37 × 63) = 2331

Step(5):

Add the number obtained in Step(1) with the number obtained in Step(4) keeping the unit place empty i.e.

2 7 3 4 3

2 3 3 1 _

5 0 6 5 3

∴ Cube of 37 = 50653

Given:

The given number = 47

Concept:

Calculation skills trick

Calculation:

Step(1):

Write down the cube of each of the digits in three digit format i.e. 4³ = 64 and 7³ = 343

The number obtained after this step is 64343.

Step(2):

Now multiply all the digit of the given number with themselves i.e. (4 × 7) = 28

Step(3):

Multiply the result obtained in Step(2) by the power 3 i.e. (28 × 3) = 84

Step(4):

Now multiply the result obtained in Step(3) with the given number i.e. (84 × 47) = 3948

Step(5):

Add the number obtained in Step(1) with the number obtained in Step(4) keeping the unit place empty i.e.

6 4 3 4 3

3 9 4 8 _

1 0 3 8 2 3

∴ Cube of 47 = 103823

Concept used:-

Trick to multiply two numbers ending in 5 with difference of 20 between them.

Method:-

• Write 125 at the end.
• Add 1 to ten’s place of the bigger number.
• Now multiply the increased digit with the ten’s digit of the smaller number.
• Write the product so obtained on the left side of 125

Calculation:-

Let the product be A125

A = (6 + 1) × 4 = 28 (step 2 and 3)

_ 1 2 5

2 8 _ _

2 9 2 5 (Final answer)

Concept used:-

Trick to multiply two digit numbers ending in 1.

Method:-

• Multiply the left most digits of both the numbers.
• Add the left most digits of both the numbers.
• Put the result from Step(2) next to the result of Step(1)
• Put 1 next to the result of Step(3)

Calculation:-

Let the product be AB1

A = 3 × 7 = 21

B = 3 + 7 = 10

AB1 = 21|10|1

Carryover of B (10) is shifted and added to 21.

Hence, 2201 is our answer.

Given:

Ratio of difference to L.C.M of two natural numbers = 4 : 21

H.C.F of two natural numbers = 6

Concept used:

If H.C.F of two natural numbers is H, then numbers should be Hx and Hy respectively. Where x and y should be relatively prime number.

Calculation:

H.C.F of two numbers = 6

Let, numbers = 6x and 6y (x, y are relatively prime number)

L.C.M of 6x and 6y = 6xy

Difference of numbers = 6x – 6y (let, 6x 6y)

⇒ (6x – 6y)/6xy = 4/21 (Given)

⇒  (x – y)/xy = 4/21

⇒ 21(x – y) = 4xy

⇒ x = 7, y = 3 (7 and 3 are relatively prime number)

Numbers = 6 × 7 = 42 and 6 × 3 = 18

Given:

H.C.F. of the two numbers = 11

L.C.M. of the two numbers = 7700

One number = 308

Formula Used: 

First Number × Second Number = L.C.M. × H.C.F.

Calculation:

308 × Other Number = 7700 × 11 

⇒ Other Number = (7700 × 11 )/308

⇒ Other Number = 275

∴ The Other Number is 275

In the given fig, ∠PQA, ∠AQB and ∠BQR forms  a linear pair.

Therefore,

∠PQA + ∠AQB + ∠BQR = 180º

(x + 20º) + (2x + 10º) + (x - 10º) = 180º

4x + 20º = 180º

\(\Rightarrow\) x = \(\frac{180^o-20^o}{4}\) = 40º

Therefore,

∠AQB= 2x + 10º = 2 x 40º + 10º = 90º

∠BQP = (x + 20º) + (2x + 10º) = 3x + 30º = 3 x 40º + 30º = 150º

∠AQR = (2x+10°)+(x−10°)=3x=3×40°=120°

We know that total surface area of cube = 6a²

So 6a² = 1014 cm²

a² = 1014/6 = 169 cm²

a = √169 = 13 cm

Thus length of cube is 13 cm.

Lateral surface area = 4a² = 4×13² = 676 cm²

Main diagonal = √3 a = √3×13 = 13√3 cm

TSA of cube = 6a²

LSA of cube = 4a²

Therefore,

TSA:LSA=6a² :4a²
 =3:2

Uses of Graphite

Graphite has been used since ancient times. It has a wide range of applications in the modern world too. Let’s look at some of the common uses of graphite below.

• Writing Materials
• Lubricants
• Refractory
• Nuclear Reactors
• Batteries
• Graphene Sheets

Uses of Cadmium 

► The element cadmium's uses are numerous. Cadmium is one of the byproducts of the primary non-ferrous industry.  

► It has several unique and remarkable characteristics. Some of them are great resistance to corrosion, excellent electrical conductance, low melting point and its excellent resistance to chemicals and high temperatures.  

► Scientists and engineers have been able to make use of these unique properties of cadmium in several important industrial applications.   

► Cadmium is used in electroplating, which is the process of coating metal by making use of an electric current. Electroplating accounts for more than 60% of cadmium use.  

► It is used in bearing alloys which has great resistance to fatigue and low coefficients of friction. Cadmium is widely used in electronic items. 

Uses of Heavy Water

India is one of the world’s largest producers of heavy water through its Heavy Water Board and also exports to countries like The United States and The Republic of Korea. Heavy water is used in certain types of nuclear reactors, where it acts as a neutron moderator to slow down neutrons. The different applications and uses of heavy water are mentioned below.

• Nuclear magnetic resonance
• In Organic chemistry
• Fourier transform spectroscopy
• Neutron moderator
• Neutrino detector
• Metabolic rate testing in physiology and biology
• Tritium production

If the seat belt is not used, the passengers are more likely to maintain its state of motion following the Newton's first law i.e law of inertia.

If the car were to abruptly stop and the seat belts were not being worn, then the passengers in motion would continue in motion. 

We need pure substances because of the following reasons: 

1. Manufacture medicines.

2. To prepare chemicals in industry.

3. For scientific purposes.

4. To maintain the good health of human beings.

A piece of muslin cloth 

Filter paper 

A bead of sand 

Charcoal

In an air conditioned building the air moves from one place to another. During its movement dust and bacteria comes in contact with it. Therefore, it is necessary to clean the return air before using it again. Air filters are used for cleaning the air 

The air filters are of following types. 

1. Viscous Filters 

2. Electric Filters

A piece of muslin cloth 

Filter paper 

A bead of sand 

Charcoal

Absolute temperature (OK or – 273.15°C).

The shape of graph between pressure P and I/V for a perfect gas at constant temperature is Straight line.

PV = nRT. Hence graph will be straight line.

(d) All molecules have same speed.

Molecules of an ideal gas moves randomly with different speeds.

3/2 K_BT  is average translational kinetic energy of a gas molecule

Low pressure and high temperature.