Explore topic-wise InterviewSolutions in Current Affairs.

Correct option is A) run off with

Correct option is B) beat them up

Correct option is B) Kick

Churchill Brothers

Correct option is B) Helen’s

Correct option is B) Helen’s

There is a childish air in the complain telling his father to slow down his footsteps so that both of them can walk together

Correct option is A) who

Correct option is C) must

Correct option is E) by giving off a little heat it keeps the weather from becoming too cold.

Correct option is B) must

Correct answer is Apu

Correct option is C) who

Correct option is B) to be designed

Correct option is D) whose

(a). Magnetite

Galena - PbS; 

Iron pyrites - FeS_2​

Magnetite - Fe₃​O₄​;

Copper glance - Cu₂​S

Option : (A)

Focal length of a lens does depend on the refractive index of lens material w.r.t. the surrounding medium.

(a) Both A and R are true and R is the correct explanation of A .

 Focal length of a lens does depend on the refractive index of lens material w.r.t. the surrounding medium.

Option : (A) 

Wavelength of sound is of the order of 1m and size of opening is much smaller. 

Therefore,

Sound is not diffracted.

Magnetic field due to a long wire

B = μ x 2I / 4π r where I is current and μ / 4π = 10^-7 , r is distance from the wire

Putting the values

B = 10^-7 x 2 x 1 / 1

= 2 x 10^-7 T .

earth’s magnetic field = 45 x 10^-6 T = 450 x 10^-7

So the magnetic field is 225 times less strong than earth’s magnetic field .

a. To avoid obscuration of details of micro-objects by diffraction effects, microscope of high magnifying power must have high resolving power.

b. R.P. of microscope \(=\frac{2\mu\,sin\,\alpha}{\lambda},\) where μsinα is termed as numerical aperture.

Thus, R.P. ∝ μsinα

c. To increase α, the diameter of objective would have to be increased. This would degrade image by decreasing resolving power.

d. Oil has higher refractive index (μ_oil > μ_air) hence to increase resolving power of microscopes of high magnifying power, the object is immersed in oil that is in contact with objective.

e. Usually cedar oil having refractive index 1.5, close to that of the objective glass is used.

(d) It is approximately constant.

(b) It is a constant-voltage device.

(b) Has a constant voltage in the breakdown region

Here I rewrite the problem with some corrections and also present a possible answer.

Question 

A horizontal force F pushes a 4kg block A which pushes against a 2kg block B. The blocks have an acceleration of 3m/s^2 to the right and there is no friction between the blocks and the surface on which they slide. What is the net force that B exerts on A?

Answer

Let  B exerts force f on A then A also exerts same force on B. 

Hence considering the net force on A we can write   F - f = 4×3 N

Again considering the net force on B we can write   f =  2×3 N= 6 N

Hence B exerts 6 N force on A

.

We have -log ( 1.1001×10^-7)

By logarithm product rule i.e 

log_a(m.n) = log_a m + log_a n

we have, 

= -(log1.1001 + log10^-7)

= -log1.1001 - log10^-7

= - 0.0414 + 7log10

= -0.0414 + 7

= 6.9586

Correct option(b)

Explanation:

The p.d. of the wire between the +ve end to jockey becomes equal to the e.m.f of the experimental cell

Correct option(a)

Explanation:

Let e.m.f of cell is proportional to ‘I₁’ when length of wire is I, balance point obtain at I/3 length. i.e., I₁ = I/3. 

If length of wire varies, balance point will obtain at length one third of total length of wire of potentiometer. 

Now total length of wire = 3I/2 

Balance point obtained at = 1/2

Correct option is A) her 

Correct option is C) it is

Correct option is  C) am

Correct option is  B) don’t

(a) The teacher advised me to take care of my health.

(b) My mother told me that I was a naughty boy.

(c) Ram told me that he liked banana.

Correct option is C) are

(a) The teacher asked me where the book was.

(b) My mother prayed that I might succeed in my examination.

(c) He said that God is everywhere.

Correct option is D) thin

Correct option is  D) well

Correct option is A) difficult

There are several proofs to regard the earth as a spherical shape of the Earth.

a. Heavenly bodies appear to be spherical: The Sun, the Moon and other heavenly bodies appear to be spherical when viewed from different position. The earth is one of them and hence it must also be spherical in shape.

b. The Lunar Eclipse: The lunar eclipse proves that the Earth is in spherical shape. During lunar eclipse when the Earth is between the Sun and the Moon, the shadow of the Earth falls on the Moon. Aristotle was the first scholar to show this by looking at the shadow of the Earth on the lunar surface. Later, this was ascertained by Ptolemy. This is considered to be the oldest proof in respect of the shape of the Earth. 

c. Sunrise and Sunset: The time of Sunrise and Sunset is not the same everywhere in the world. This is due to spherical shape of the Earth. If the Earth were to be flat all places on the Earth would have had sunrise and sunset at the same time everywhere in the world.

d. Circumnavigation: Circumnavigation of the world can only be possible when the Earth is in spherical shape. If one start on a sea voyage towards the east, by moving constantly in the same direction, he would be able to complete a circle of the world and reach the original point form where he had started.

e. The Bed Ford level experiment: Dr.Alfred Russel Wallace conducted an experiment in 1956, along the Bed Ford level canal area in Britain. It is the most convincing proof of the curvature of the Earth. He fixed three poles of same height at an interval of about mile apart and observed through a telescope. It was found that the pole in the middle was higher than other two poles. It is due to the curvature of the Earth. If the Earth were to be flat all the poles would have the same horizontal level.

f. Sighting a ship: A ship on the sea approaching the coast, when seen from the short does not come into view all at once. The observer first sees the mast and then the hull and finally the whole ship. A ship moving away from the coast disappears gradually and finally out of view. If the Earth were to be flat the whole ship would have come into view. 

g. Aerial and Satellite Photographs: The photographs taken by the cosmonauts in the recent decades and satellites have provided ample proof to show that the earth is spherical in shape. 

Mathematics is a deductive system in which one starts from some definitions, some undefined terms and some self-evident truths (which may be based on experience) called axioms. Writing proofs in geometry implies argument or justification of statements.

• As in all mathematical theories, Euclid built a theory involving some abstract objects and relationships between them. Some of the objects are undefined, for example, 'point', 'line', etc. Others are defined in terms of these objects. Of course, the effort is to keep the number of undefined terms to a minimum.
• Each theorem in Euclid's geometry is proved from some preceding results. Of course, he started with a set of five assumptions about the undefined terms, which are the axioms or postulates of the theory. Any set of statements can be laid down as postulates so long as they do not lead to any logical contradictions or inconsistencies. Obviously, the fewer the postulates, the better. Mathematicians try to derive more and more theorems from fewer and fewer postulates. 

Thus from the above-mentioned points, it is clear that writing proofs in geometry imply argument or justification of statements.

There are several proofs to regard the earth as a spherical shape of the Earth.

a. Heavenly bodies appear to be spherical: The Sun, the Moon and other heavenly bodies appear to be spherical when viewed from different position. The earth is one of them and hence it must also be spherical in shape. 

b. The Lunar Eclipse: The lunar eclipse proves that the Earth is in spherical shape. During lunar eclipse when the Earth is between the Sun and the Moon, the shadow of the Earth falls on the Moon. Aristotle was the first scholar to show this by looking at the shadow of the Earth on the lunar surface. Later, this was ascertained by Ptolemy. This is considered to be the oldest proof in respect of the shape of the Earth.

c. Sunrise and Sunset: The time of Sunrise and Sunset is not the same everywhere in the world. This is due to spherical shape of the Earth. If the Earth were to be flat all places on the Earth would have had sunrise and sunset at the same time everywhere in the world. 

d. Circumnavigation: Circumnavigation of the world can only be possible when the Earth is in spherical shape. If one start on a sea voyage towards the east, by moving constantly in the same direction, he would be able to complete a circle of the world and reach the original point form where he had started. 

e. The Bed Ford level experiment: Dr.Alfred Russel Wallace conducted an experiment in 1956, along the Bed Ford level canal area in Britain. It is the most convincing proof of the curvature of the Earth. He fixed three poles of same height at an interval of about mile apart and observed through a telescope. It was found that the pole in the middle was higher than other two poles. It is due to the curvature of the Earth. If the Earth were to be flat all the poles would have the same horizontal level.

f. Sighting a ship: A ship on the sea approaching the coast, when seen from the short does not come into view all at once. The observer first sees the mast and then the hull and finally the whole ship. A ship moving away from the coast disappears gradually and finally out of view. If the Earth were to be flat the whole ship would have come into view. 

g. Aerial and Satellite Photographs: The photographs taken by the cosmonauts in the recent decades and satellites have provided ample proof to show that the earth is spherical in shape.

Rotation of the Earth causes various effects. They are: 

a. Day and night caused by the rotation of the earth on its axis. This is because parts of the earth which face the sun have day and the parts which do not face the sun have night. This happen with precision and progression and not suddenly – The time when the sun beings to cast its light in the sky is known as dawn. At noon. The sun is overhead. At dusk, it is twilight and the sun is seen disappearing in the sky. At night, it is completely dark.

b. The duration of the day and night is not equal at all places on the earth because of the inclined axis. The length of days varies with respect to the seasons as well as latitude

c. The sun, the moon and the stars seem to move from east to west. This is because the earth spins from west to east. This effect is similar to what one experiences while looking at trees from a moving train. 

d. The speed of rotation has created a centrifugal force resulting in a bulge in the middle portion of the earth and flattened top at the poles.

e. The earth’s rotation affects the movement of water in the oceans. The tides are deflected because of the rotation of the earth. 

f. Rotation causes difference in time over various places on the earth. 

g. The Earth acts as huge magnet: The one end of the needle of the compass always points towards the north magnetic pole. That means, the earth acts as a magnet. The rotation . of the earth causes the earth to act as a magnet.

h. Rotation of the Earth influences the movement of ocean water, particularly ocean currents. 

i. The rise and fall in the sea level is called tides. Rotation of the Earth causes the lacing of water bodies to the Moon. The gravitational attraction of the Moon and position of the water bodies cause tides. This is a regular phenomenon due to Earth’s rotation.

A. False It is synchronous with mitral and tricuspid closure. 

B. False It corresponds with the QRS complex. 

C. True The mitral and tricuspid valves bulge back into the atria. 

D. True This closes the mitral and tricuspid valves. 

E. False It corresponds with the C wave; the A wave is due to atrial contraction which precedes the first heart sound.