Explore topic-wise InterviewSolutions in Current Affairs.

Difference between A.C. and D.C.: The alternating current (A.C.) reverses its direction periodically whereas the direct current (D.C.) always flows in one direction. A.C. is preferred over D.C. because it can be transmitted over long distance without much loss of energy

D.C. source: Battery 

A.C. source: A.C. generator

Magnetic field (B) at the centre of the circular coil 

(i) increases if the current is increased as B ∝ I 

(ii) reverses on reversing the current. 

(iii) increases if the number of turns in the coil increases as field is directly proportional to the number of turns

(a) The direction of force experienced by the current-carrying conductor depends on: 

(i) direction of current and 

(ii)direction of magnetic field. 

(b) When the direction of current is at right angle to the direction of magnetic field, the force is maximum. 

(c) No force is experienced by the proton beam. As proton beam is moving along the direction of magnetic field.

No, because circular coil is placed in a constant magnetic field produced by a steady current of 5A.

(i) Two errors are:

(a) Fuse is incorrectly connected to the neutral wire (N), it must be connected to the live wire(L).

(b) Bulb B2 is connected to the neutral wire.

(c) Two switches S₁ and S₂ in both B₁ circuit and no switch in bulb B2 circuit.

(ii) Element of electric heater-high melting point

Element of fuse wire-Low melting point 

(iii) (a) Each application has equal potential difference.

(b) Each appliance has separate switch to ON/OFF the flow of current through it.

Direction of magnetic field: Imagine the current carrying solenoid in your right hand such that the curled fingers are in the direction of current, then the extended thumb will indicate the direction of emerging magnetic field line, i.e. the face of solenoid which has North polarity.

(i) Following are the errors in the circuit given above. a) Fuse is incorrectly connected to the Neutral wire (N) it must be connected to the live wire (L). b) Bulb B2 is not connected to the neutral wire. 

(ii) Element of electric heater has high melting point in order to stand high temperatures while element of fuse has low melting point. 

(iii) 1. Each appliance will have and equal potential difference. 

2. Each appliance will have a separate switch to ON/OFF the flow of the current.

A = south pole, B =North Pole.

When north pole of a bar magnet is brought near to end connected to negative terminal of battery then solenoid repels bar magnet. It means the end of a solenoid which is connected to the negative terminal of the battery behaves as a north pole.

(i) The current in first case is the Direct current because it is constant with the time. The current in second case is the Alternating current because its direction and magnitude changes continuously with the time. 

(ii) Source of direct current are solar cell, fuel cell etc. Source of alternating current the electricity coming to our home. 

(iii) The frequency of the Alternating current in India is 50 Hz. 

(iv) 

Two advantages :

(i) To have equal potential difference across each appliance. 

(ii) Each appliance has a separate switch to ON / OFF the flow of current through it so that each circuit can work independently

(i) No, because, a charged particle at rest does not interact with the magnetic field.

(ii) No, because, the force is zero if current and field are in the same direction.

(iii) Yes, because, the force is maximum when the current and magnetic field is maximum.

Plasmodium is reproduces by Multiple fission.

 Room heater and geyser.

(i) Towards south in upward direction.

(ii) Towards west in upward direction.

(iii) Towards upward direction.

According to Fleming’s left hand rule in horizontal plane towards west.

The magnetic field is directly proportional to the number of turns in the magnet. Therefore on increasing the number of turns the magnetic field will increase because, with addition of each turn there will be an increase in number of charge carriers that contribute to the field at a point.

In binary fission, two daughter cells are formed and in multiple fission, many daughter cells are formed simultaneously. 

Plasmodium which is a malarial parasite reproduces. by multiple fission.

Using Fleming’s Left-Hand Rule, electron beam will be deflected towards the west.

(i) Maximum strength – at A and C 

(ii) Minimum strength – at B 

At A and C, magnetic field lines are crowded while at B, they are spread out.

(i) An organism, having an elongated and constricted nucleus.

(ii) An organism having two nuclei with a constriction in between.

The alpha particle will move in a circular path. This is because a centripetal force acts on the particle due to the movement of a particle in the magnetic field.

 Using Fleming’s left hand rule, the nature of charged particle is positive.

1. Strong nuclear force: The strong force which binds protons and neutrons (nucleons) together in the nucleus of an atom is called strong nuclear force.

Characteristics of strong nuclear force:

• It is a very strong attractive force.
• It is a short range force of the order of 10^-14 m.
• it is charge independent.

2. Weak nuclear force: The force of interaction between subatomic particles which results in the radioactive decay of atoms is called weak nuclear force.

Characteristics of weak nuclear force:

• It acts between any two elementary particles (pair of subatomic particles).
• It is a stronger force than gravitational force.
• It is much weaker than electromagnetic force or strong nuclear force.
• It is a short range force of the order of 10^-16 m. 

The correct option is B) a base.

The correct option is A) magnesium oxide.

No all the materials react with oxygen in the air.

An alloy of mercury metal with one or more other metals is known as an amalgam.

Vinegar - Acetic acid

Tamarind - Tartaric acid and citric acid.

(b) oxidation

Pure gold is said to be of 24 carats. It is not suitable for making ornaments because it is very soft.

Gold in an extremely malleable metal. Pure gold is too soft to make jewellery out of it. Hence 24 Karat pure has to be mixed with other metals to make it hard gold enough to be used as jewellery piece.

Metals like gold and silver, even if they are exposed to air for a long time, they do not change colour or get rusted. 

It means that they are resistant to corrosion which is the reason why we use them in making ornaments.

Given: m = 1.5 ton = 1500 kg,

u = 72 kmph = 72 × \(\frac{5}{18}\) m/sm/s = 20 m

s^-1 (on turning engine off),

v = 0, t = 20 s, s = 50 m

To find: Braking force (F)

Formula:

i. v = u + at

ii. v² – u² = 2as

iii. F = ma

Calculation:

On turning the engine off,

From formula (i),

a = \(\frac{0-20}{20}\) = -1 m s^-2

This is frictional retardation (negative acceleration).

After seeing the accident,

From formula (ii),

a₁ = \(\frac{0^2-20^2}{2(50)}\) = -4 m s^-2

This retardation is the combined effect of braking and friction

∴ braking retardation =4 – 1 = 3 m s^-2

From formula (iii), the braking force, F = 1500 × 3 = 4500 N

The braking force is 4500 N.

Due to geological changes. molten rocks formed in the deeper hot region of earth's crust are pushed upward and trapped in certain region- hotspots are formed.

When underground water comes in contact with hotspots steam is generated.

The steam routed through pipe to a turbine and produce electricity.

Geothermal energy is heat energy trapped in hot regions called hot spots when molten rocks are pushed upwards. When underground, water comes in contact with hot spots steam is generated. Steam trapped in rocks is routed through a pipe to a turbine to generate electricity.

Very few commercially viable sites are available where such energy can be exploited.

Detailed Answer:

The heat from the interior of the earth can be utilized as a source of energy under certain favorable conditions that are created by natural processes. This is known as geothermal energy.

Molten rocks formed in the deeper hot regions of Earth's crust are pushed upward and trapped in certain regions due to geological changes. These spots are called hot spots. Underground water when comes in contact of hotspots, it gets converted into steam due to heat of molten rocks (magma) and remains trapped between the rocks, at high pressure. This steam can be used to run turbines connected to electric generators.

Solar cooker, solar water heater.

Hot iron emits infrared rays. These rays are invisible to the eves.

Since Breaking load = Breaking Stress x Area; so if cable is cut to half of its original length, there is no change in its area hence there is no effect on the maximum load that the wire can support. 

1) Since for the above curves, Hooke’s law is not obeyed as the curve is not a straight line Hence such type of curve are called as elastic hysteresis as the materials do not retrace curve during unloading. 

2) Rubber B is preferred because area of loop B is more than that of A which shows more absorption power for vibrations which is useful in machinery. 

3) Since hysteresis loop is a direct measure of heat dissipation, hence rubber A is preferred over B so to minimize the heating in the car tyres. 

Ductile materials are those materials which show large plastic range beyond elastic limit. eg:- copper, Iron 

Brittle materials are those materials which show very small plastic range beyond elastic limit. eg:- Cast Iron, Glass. 

1. The Kashmir of Andhra Pradesh or Korra Bayalu

2. It is known for the snowfall with a record fall of 0°C and sometimes – 3°C temperatures particularly between November and January.

3. Winter

4. One will be frozen.

5. Kondakarla Bird Sanctuary

1. Araku Valley

2. Coffee

3. The Coffee Museum and the Tribal Museum

4. The Tribal Museum

5. The lifestyle of the tribal people

(A) untouchability

The radiant energy emitted be a body solely on account of its temperature is called thermal radiation.

Properties of thermal Radiation:- 

1) They travel through vacuum 

2) They obey laws of refraction 

3) They can be refracted 

4) They travel with the speed of light 

5) They do not heat the medium through which they passes. 

6) They exhibit phenomena of interference, diffraction and polarization.

When the solar energy falls on the top surface of the atmosphere then the following happens:
(i) Some solar energy is reflected back into the space by the atmosphere, and
(ii) The atmosphere also absorbs a lot of solar energy; for example, most of the ultraviolet rays are absorbed by the ozone layer.
So, the solar energy which reaches us through the Earth's atmosphere are mainly in the form of heat rays (infra red rays) and visible light, which is a small part of the solar energy.

LPG is considered as an ideal fuel because It is easy to store, handle and transport. It produces large amount of heat on burning. It does not leave any residue on burning,

Uses of natural gas:

(i) As a fuel in thermal power plants.

(ii) As a fuel in transport vehicles.