Explore topic-wise InterviewSolutions in Current Affairs.

(i) For short duration: Limewater turns milky due to the formation of CaCO₃, Which is insoluble in water.

Ca(OH)₂(aq) + CO₂(g) →CaCO₃(s) + H₂O(l)

Ca(OH)₂ - Lime water

CaCO₃(s)-White ppt.

(ii) For Long duration: A clear solution is obtained due to the formation of calcium bicarbonate. Ca (HCO₃)₂ Which is soluble in water

CaCO₃(s)+ H₂O(l)+CO₂(g) → Ca(HCO₃)₂(aq)

Diabetes is the correct answer. 

Common defects of the eye:

(i) Near or short sightedness (Myopia)

(ii) Far or long sightedness (Hypermetropia)

(iii) Astigmatism.

(iv) Presbyopia.

(v) Night blindness.

(vi) Colour blindness.

(vii) Squint.

(viii) Cataract.

LiI + KF → LiF + KI;

larger cation stabilizes larger anion and smaller cation stabilizes smaller anion.

Electromagnetic wave: When an electric field and magnetic field are perpendicular to each other and at right angles to the direction of propagation of the wave is formed. Such a wave is called an electromagnetic wave.

Electromagnetic spectrum: The entire, range of electromagnetic wave frequencies is known as the electromagnetic spectrum.

Sukhasana facilitates physical and mental balance without causing strain or pain in the legs. It easily leads to a deeper concentration. It helps in curing Asthmatic disorders.

In this asana, one sits with legs straight in front of the body. The right leg is bent and place the foot under the left thigh. Now bend the left leg and the foot placed under the right thigh. The hands are placed on the knees or in Jana Mudra. The head, neck and back are kept upright but without any strain, the eyes are closed and the whole body is kept relaxed.

Sukhasana is the easiest and most comfortable of the meditation postures. It can be utilized, without any ill effects, by persons who are unable to perform difficult meditation asanas. It is a relaxing posture which may be used after Siddhasana or Padmasana.

1. Circulatory system: Circulatory system is a transport system moving substances throughout our body with the help of blood.

2. Arteries: Arteries are the blood vessels in which oxygenated blood is going away from the heart to all parts of the body.

3. Veins: Veins are the blood vessels which carry deoxygenated (impure) blood from the body cells to the heart.

In his early years, Newton was chiefly remarkable in his ability to invent things. He had manufactured a set of little tools and saws of various sizes. With the help of these things, he invented curious articles, at which he worked with so much skill. His friends and neighbours admired at the things manufactured by him. Some of his friends advised his grandmother to apprentice him to a clock maker because, besides his mechanical skill, Newton seemed to have a taste for mathematics, which would be very useful to him in that profession. After sometimes he could set up one for himself.

Old Stone age man 

1. He was a nomad. 

2. Took shelter on branches of trees, in holes and caves. 

3. Wore dresses made out of leaves, skin of animals and barks of trees.

4. Ate vegetables, fruits and roots which he gathered from jungles.

5. Not civilized.

Present day man:

1. Settled in villages and towns.

2. Lives in well built houses.

3. Wears dresses made out of cotton and other materials.

4. Eats all kinds of food grains.

5. Well civilized.

(i) f is a rational function of the form g(x)/h(x), where g (x) = x and h (x) = x² + 3x + 2.

Now h (x) ≠ 0 ⇒ x² + 3x + 2 ≠ 0 ⇒ (x + 1) (x + 2) ≠ 0 and hence domain of the given function is R – {– 1, – 2}.

(ii) f (x) = [x] + x,i.e., f (x) = h (x) + g(x)

where h (x) = [x] and g (x) = x

The domain of h = R and the domain of g = R. Therefore 

Domain of f = R

Correct option is (B) Weightlifting

While playing different games and sports, sometimes, players suffer serious physical injuries. In a boxing match, one boxer knocks down the other to the floor. In horse racing, he risks the injury to his vertebrae and spine. Thus the players) are very often seriously injured and sometimes they happen to lose their lives as well.

There are many advantages of being a player. A good player enjoys playing. He can also earn handsome money. Their dresses and heroic deeds are really enviable. They become famous the world around and gain many privileges. They win a lot of appreciation and get a number of awards. They play enthusiastically and turn to be role models for youngsters. In this age of e-media, a large number of people in the native country and abroad become their followers and get a large fan-following.

The poet is full of praise for players. The poet says that some players play quite enthusiastically. But while playing, they suffer several physical injuries. Sometimes, the injuries are too serious. They play heroically and risk their lives, too. The poet is ready to buy expensive tickets to watch the athletes play on the field.

The parts of human body mentioned in this poem are : heart, vertebrae and spine.

The poet is ready to drink (wine) to them (the players) or eat with them. He is ready to do anything for them. He is ready to buy very expensive tickets to watch them play in the stadium. But he would never swap his position with one of theirs. He would never be a player. He would be happy being a spectator viewer for ever.

We like Wangjia the most in the story. He was so young to take such a risk. We like his selfless hard work. He did a great task for the benefit of his people. He faced many hardships during his task. He didn’t care about his life also. To work for others is really a good job. everyone will appreciate his work.

(b) \(\frac{mv_1}{m + M}\)

A) 0.7 kg/s

Explanations:

F = d/dt (mv) = v dm/dt

⇒  210 = 300 * dm/dt

⇒  dm/dt = 0.7 Kg/s

Answer is (B) 1/2 kT.

Rate of diffusion of a gas is inversely proportional to the square root of the density. So hydrogen leaked out more rapidly.

Try our Ray Optics and Optical Instruments Class 12 Mock Test and learn with fun. Many students do not like ray optics and optical instruments section. For the exam perspective, it is an important one. Free Class 12 Online Mock Test  Ray Optics and Optical Instruments for important topics of all chapters in JEE Physics Ray Optics and Optical Instruments book. Practice mock test many times and check your score. Practicing online mock test will help you to check your understanding and identify areas of improvement. 

If you want to get more marks in Physics Ray Optics and Optical Instruments class tests and exams then Practice these online mock tests for Ray Optics and Optical Instruments designed as per the latest class 12 syllabus. Our teachers have provided the MCQ questions based on the Class 12 Online Mock test Ray Optics and Optical Instruments. You should practice these Class 12 Ray Optics and Optical Instruments Online Tests having objective-based questions and compare your answers with the solutions provided by us.

Click here to start practice: - Class 12 Ray Optics and Optical instruments Mock Test

Correct option (D) H₂Te 

(B)   +13 kJ mol^-1 

Answer is (D) Bihar

Impulse

Impulse is given by the product of force and time. Since force is a vector quantity, its product with time (a scalar quantity) gives a vector quantity.

Impulse
Impulse is given by the product of force and time. Since force is a vector quantity, its product with time (a scalar quantity) gives a vector quantity.

(a) Meaningful
(b) Not Meaningful
(c) Meaningful
(d) Meaningful
(e) Meaningful
(f) Meaningful

Explanation:

(a) The addition of two scalar quantities is meaningful only if they both represent the same physical quantity.
(b) The addition of a vector quantity with a scalar quantity is not meaningful.
(c) A scalar can be multiplied with a vector. For example, force is multiplied with time to give impulse.
(d) A scalar, irrespective of the physical quantity it represents, can be multiplied with another scalar having the same or different dimensions.
(e) The addition of two vector quantities is meaningful only if they both represent the same physical quantity.
(f) A component of a vector can be added to the same vector as they both have the same dimensions.

With 0.5 efficiency, 1 litre generates 1.5 × 10⁷J, which is used for 15 km drive.

F d = 1.5 ×10⁷J. with d = 15000 m

F = 1000 N : force of friction.

1 J = 0.24 calorie

Work done by the force of gravity (which provides the centripetal force) is zero as the force of gravity acting on the satellite is normal to the displacement of the satellite.

(a) At position A, pendulum has maximum kinetic energy and its potential energy is zero at its resting position. Hence, K=mgh and U= 0.

(b) At B, kinetic energy decreases and potential energy increases. Hence, K= 0 and U=mgh

(c) At C also, kinetic energy K= 0 and potential energy U=mgh.

(a) Kinetic energy (K)

(b) Potential energy (U)

(c) Kinetic energy (K)

(d) Potential energy (U)

(e) Kinetic energy (K)

(f) Potential energy (U)

Here total initial mass (²³⁵₉₂U + ¹₀n)

= 235.04 + 1.0087 = 236.0487 u

Total final mass (¹⁴⁵₅₆Ba + ⁹⁶₃₆Kr + 3¹₀n) = 235.8621 u

Change in mass = 236.0487 - 235.8621 = 0.1866 u

Energy released = 0.1866 x 931 = 173.72 MeV

Answer is (C) mu

Collision is assumed to be elastic 

B) Isothermal charges

Explanations:

• Boyle's law states that at constant temperature, for a fixed mass of a gas, PV = constant
• But if the temperature remains constant, it will be called as an isothermal change so B is correct.

The gradual decrease of useful energy due to friction etc. is called the degradation of energy.

Examples:

1. When we cook food over a fire, the major part of heat energy from the fuel is radiated out in the atmosphere. This radiated energy is of no use to us.

2. When electrical appliances are run by electricity, the major part of electrical energy is wasted in the form of heat energy.

(a) Potential energy of the ball = mgh

= 2 x 10 x 5 =100J

(b) Kinetic energy of the ball just before hitting the ground = Initial potential energy= mgh = 2 x 10 x 5 =100J

(c) Mechanical energy converts into heat and sound energy.

(a) Potential energy at the greatest height = initial kinetic energy

or, mgh = 1/2 mv² 

= 1/2 ×0.500 ×15 ×15=56.25J

(b) Kinetic energy on reaching the ground= potential energy at the greatest height = 56.25 J

(c) Total energy at its half-way point = 1/2 (K + U) = 56.25J.

C) 4 N

Let vector p and q then

|p-q| ≤   |r| ≤  |p+q|

Using this concept

Take p=5 and q= 10 So

|5-10| ≤  |r| ≤ |5+10|

|-5| ≤   |r| ≤   |15|

5 ≤   |r| ≤   15

So range should between 5 to 15 and this range 4 is not present. 

(i) Work done in raising a 50kg mass to a height 2m against the force of gravity is:

W = mg × h = mgh

Hence both men will do the same amount of work. Hence,

work done by A/work done by B = mgh/mgh = 50 x 10 x 2/50 x 10 x 2 = 1/1 = 1: 1

(ii) First man A takes 2 minutes to raise 50 kg mass

Second man B takes 5 minutes to raise 50 kg mass.

Power developed by man A = work done/Time taken mgh/t = 50 x 10 x 2J/120S = 25/3W

Power developed by man B = work done/Time taken = mgh/t = 50 x 10 x 2J/5 x 60s = 10/3 W

Power developed α 1/time taken

Power developed by A/Power developed by B = (25/3)/(10/3) = 25/10 = 5/2 = 5 : 2

i) Down a group : When we move from top to bottom in a group, the metallic character increases.

ii) Across a period: When we move left to right in a period, the metallic character decreases.

i) Y has low nuclear charge.

ii) X has lower atomic size,

iii) X has higher ionization energy.

iv) X has high electronega^vity.

v) Y has more metallic character.

Position and momentum (or velocity) of particle are uncertain in uncertainty principle. Mathematically, Δ_x× Δ_p ≥ h /4π

Or Δ_x × Δ(mv_x ) ≥ h/ 4π

Or Δ_x × Δv_x ≥ h/ 4πm

Where, Δ_x = uncertainty in position

Δ_p = uncertainty in momentum

Δv_x= uncertainty in velocity

Reactivity of Noble gases : 

1. The noble gases show extremely low chemical reactivity. 

2. He and Ne do not form chemical compounds. 

3. Xenon, krypton and argon show only minor reactivity. 

4. The reactivity order follows like this : Ne < He < Ar < Kr < Xe < Rn. 

5. Xenon can form compounds like XeF₂ , XeF₄ and XeF₆, etc.

Reasons for low reactivity :

1. The extremely low reactivity of noble gases is due to stable electronic configuration. 

2. But as we move from top to bottom the reactivity increases. So xenon can form some compounds with high electronegative elements.

(a) Human heart rate is about 70 beats/min. More the characteristic length of the mammal, smaller is the heart-beat rate.

(b) As scale factor of a human relative to a rhesus monkey is about 2.5, therefore, monkey's heart beat rate is 70 x 2.5 = 175