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Yes, it is possible that a trait is inherited but may not be expressed. 
For example, when pure tall pea plants are crossed with pure dwarf pea plants, only tall pea plants are obtained in F₁ generation.

On selfing tall plants of F₁, both tall and dwarf plants are obtained in F₂ generation in the ratio 3 : 1. Reappearance of the dwarf character, a recessive trait in F₂ generation shows that the dwarf trait was present in individuals of F₁ but it did not express.

The capacity of substance or an object doing any work is called energy.

Coal is an extremely important energy resource. It has several varieties based on the degrees of compression and the depth and time of burial. The following are the different varieties of coal:

Lignite – This is the lowest quality of coal as it has the least carbon concentration. It is soft brown coal with high moisture content and mainly used in electricity generation.

Bituminous – This is middle-quality coal with a high heating value. While it appears shiny and smooth, it may reveal a layered appearance on closer inspection. This type is highly popular for commercial use.

Anthracite – This is the highest quality of coal with a lustrous black appearance. It is hard and brittle with a high percentage of fixed carbon and a low percentage of volatile material. It is mainly used in metal smelting and fabrication industries.

Peat – contains less than 40-55 per cent of carbon. It also contains a sufficient amount of volatile matter and a lot of moisture.

In India, lignite deposits are found in Neyveli in Tamil Nadu.

Correct answer is Atomic age

The gradual unfolding of organisms from pre- existing organisms through changes since the beginning of life is called evolution.The theory proposed byJ.B. Lamarck is known as the theory of inheritance of acquired characters. According to this theory, the use and disuse of an organ leads to acquiring of change in that organ. These changes or variations can be passed on from one generation to the next but this idea of inheritance of acquired characters was soon discarded.

Yes, it is possible that a trait is inherited but may not be expressed.
For example, when pure tall pea plants are crossed with pure dwarf pea plants, only tall pea plants are obtained in F₁ generation.

On selfing tall plants of F₁, both tall and dwarf plants are obtained in F₂ generation in the ratio 3 : 1. Reappearance of the dwarf character, a recessive trait in F₂ generation shows that the dwarf trait was present in individuals of F₁ but it did not express.

The electricity produced by coal, diesel and natural gas is called thermal energy.

Correct option is (a) 3, 1, 4, 2, 5

The modern age is also known as atomic age.

Yes, the scientist may arrive at the law of dominance according to which the trait that is expressed in the F₁ generation is the dominant trait, although both the dominant and recessive traits are present in the F₁ generation. In the F₂ generation, the recessive traits are also expressed along with the dominant traits.

Guru Gobind Singh Ji spent the first five years of his childhood at Patna Sahib. His maternal uncle Shri Kirpal Chand was his guardian. It is said that a Muslim saint named Bhikhan Shah from Ghuram (Patiala district^ visited Patna Sahib to have the divine glimpse of the child Gobind. The moment the Muslim saint looked at the child for the first time, he forecasted that the child would become a great man and lead the people on the right path. The forecast of the Muslim saint came out true. The signs of his greatness were visible even in his childhood. The child Gobind Das used to divide his friends into groups and organise mock battles. The child Gobind Das used to pay them even salaries in the form of sweets and cowries (small shells). The child Gobind Das used to play the role of a judge and settled disputes of his playmates. The child Gobind Das used to deliver judgements with great ability.

Igneous rocks may also be classified as acidic or basic depending on their composition. The acidic rocks contain more than 65% silica and very low percentage of oxides. These are Arundeep’s Self-Help to Voyage-7 less dense and light coloured. For example, granite. The basic rocks contain low percentage of silica and high percentage of oxides. These are dense and dark coloured. For example, basalt.

Correct answer is (a) hand-picking

A unit is defined as the standard of reference chosen to measure any physical quantity. 

According to Fresnel, diffraction is the result of superposition of secondary waves starting from different parts of the same wavefront.

(i) Spherical wavefront
(ii) Plane wavefront.

The uncertainty in the speed is 2% i.e.

45 x \(\frac{2}{100}\) = 0.9 m/s

According to Heisenberg uncertainty,

∆x × m∆v = \(\frac{h}{4\pi}\)

\(\therefore\) ∆x = \(\frac{h}{4\pi m\Delta v}\)

= \(\frac{6.626\times10^{-34}Js}{4\times3.14\times40\times10^{-3}kg\times0.9m/s}\)

=1.46 × 10⁻³³ m

This is nearly ~10¹⁸ times smaller than the diameter of a typical atomic nucleus.

Given, m = 150 g = \(\frac{150}{1000}\)kg = 1.5 x 10^-2 kg

Uncertainty in position (∆x) = 1Å = 1 × 10⁻¹⁰m

Uncertainty in velocity (∆v) = ?

According to Heisenberg uncertainty principle,

∆x × ∆p = \(\frac{h}{4\pi}\)

∆x × m(∆v) = \(\frac{h}{4\pi}\)

\(\therefore\) ∆v = \(\frac{h}{4\pi m \times\Delta \mathrm{x}}\)

= \(\frac{6.626\times10^{-36}J.sec}{4\times3.14\times1.5\times10^{-2}kg\times1\times10^{-10}m}\)

= 3.5 × 10⁻²⁴ m/s.

Metallic character of IA group elements : 

1. Alkali metals exhibit many of the physical properties common to metals but their densities are lower than those of other metals.

2. Alkali metals have one electron in their outer shell which is loosely bound. 

3. They have largest atomic radii of the elements in their respective periods. 

4. The lower ionization energies result in their metallic properties and high reactivities. 

5. An alkali metal can easily lose its valence electron to form positive ion.

6. So they have greater metallic character. 

7. The metallic character increases as we move from top to bottom in group due to addition of another shell, it is easy to lose electron.

Yes, a moving cricket ball has a wave character. It possesses wave length which is called de Broglie wave length and is given by the equation –

λ = h/mv = h/p

In 6 km there are 6000 steps.

E = 6000 (mg)h

= 6000 × 600 × 0.25

= 9 × 10⁵J.

This is 10 % of intake.

Intake energy = 10 E = 9 ×10⁶J.

Kinetic energy of the body changes to potential energy when it is thrown vertically upwards and its velocity becomes zero.

Answer is (D) c ∝ 1/√d

PV = RT Or PM = RTd. If P is constant, then T ∝ 1/d. But T∝ Q².

Hence C ∝ 1/√d. 

Potential energy of the ball at the highest point is mgh.

Hint: At the highest point, the ball momentarily comes to rest and thus its kinetic energy becomes zero.

Potential energy at the maximum height= initial kinetic energy

= 1/2 mv²

= 1/2×0.20 ×20 ×20=40J

Answer is (C) R ∝ 1/√d.

It is in accordance with the graham’s law of diffusion. 

The sum of its kinetic and potential energy remains constant throughout the motion.

Hint: In accordance with law of conservation of mechanical energy, whenever there is an interchange between the potential energy and kinetic energy, the total mechanical energy remains constant.

P.E. = mgh = m x 9.8 x 1.5 J.

Since 5% of energy is lost, so

P.E. = m x 9.8 x 1.5 x 95/100

But, this energy is converted to K.E.

K.E. = P.E

1/2 mv² = m x 9.8 x 1.5 x 95/100

v = √{2 x 9.8 x 1.5 x 95/100} = 5.29 ms^-1

It states that work done by a force acting on a body is equal to the change produced in the kinetic energy of the body.

(b) Potential energy

Hint: P.E. is the energy possessed by a body by virtue of its position.

Work is done only in case of a boy climbing up a stair case.

Elastic potential energy is possessed by wound up watch spring

The work done is said to be of 1 Joule if 1 newton of force displaces a body through one metre in its own direction.

(a) Electrical energy into sound energy

(b) Heat energy into mechanical energy

(c) Sound energy into electrical energy

(d) Electrical energy to mechanical energy

(e) Electrical energy into light energy

(f) Chemical energy to heat energy

(g) Light energy into electrical energy

(h) Chemical energy into heat energy

(i) Chemical energy into electrical energy

(j) Chemical energy to mechanical energy

(k) Electrical energy into heat energy

(l) Light energy into electrical energy

(m)Electrical energy into magnetic energy.

(a) Potential energy of wound up spring converts into kinetic energy.

(b) Chemical energy of petrol or diesel converts into mechanical energy (kinetic energy)

(c) Kinetic energy to potential energy

(d) Light energy changes into chemical energy

(e) Electrical energy changes into chemical energy

(f) Chemical energy changes into heat energy

(g) Chemical energy changes into heat and light energy

(h) Chemical energy changes into heat, light and sound energy

The six different forms of energy are:

1. Solar energy

2. Heat energy

3. Light energy

4. Chemical or fuel energy

5. Hydro energy

6. Nuclear energy

Potential energy: The energy possessed by a body by virtue of its specific position (or changed configuration) is called the potential energy.

Different forms of P.E. are as listed below:

(i) Gravitational potential energy: The potential energy possessed by a body due to its position relative to the centre of Earth is called its gravitational potential energy.

Example: A stone at a height has gravitational potential energy due to its raised height.

(ii) Elastic potential energy: The potential energy possessed by a body in the deformed state due to change in its configuration is called its elastic potential energy.

Example: A compressed spring has elastic potential energy due to its compressed state.

The rate of doing work is called power. The S.I. unit of power is watt (W).

The energy of a body is its capacity to do work. Its S.I unit is Joule (J).

True, magnitude of velocity of a body moving in a straight line may be equal to the speed of the body.

Further, magnitude of any sort of quantity is a pure and positive red number and has no direction, hence the magnitude of a vector is always a scalar.

The answer is Linear momentum.

a) True 

b) False 

c) False 

d) True 

e) True

Explanation:

a) The magnitude of a vector is a number. Hence, it is a scalar. 

b) Each component of a vector is also a vector. 

c) Total path length is a scalar quantity, whereas displacement is a vector quantity. Hence, the total path length is always greater than the magnitude of displacement. It becomes equal to the magnitude of displacement only when a particle is moving in a straight line. 

d) It is because of the fact that the total path length is always greater than or equal to the magnitude of displacement of a particle. 

e) Three vectors, which do not lie in a plane, cannot be represented by the sides of a triangle taken in the same order. 

(a) True
(b) False
(c) False
(d) True
(e) True

Explanation:

(a) The magnitude of a vector is a number. Hence, it is a scalar.
(b) Each component of a vector is also a vector.
(c) Total path length is a scalar quantity, whereas displacement is a vector quantity. Hence, the total path length is always greater than the magnitude of displacement. It becomes equal to the magnitude of displacement only when a particle is moving in a straight line.
(d) It is because of the fact that the total path length is always greater than or equal to the magnitude of displacement of a particle.
(e) Three vectors, which do not lie in a plane, cannot be represented by the sides of a triangle taken in the same order.

eV measures the energy of atomic particles.

1eV = 1.6 × 10^-19J

Answer is (B) 1030

Temperature difference between places also causes winds and Rains

(1) The threshold frequency for a given metal surface is the characteristic minimum frequency of the incident radiation below which no photoelectrons are emitted from that metal surface (whatever may be the intensity of incident light).

(2) The threshold wavelength for a given metal surface is the characteristic maximum wavelength of the incident radiation above which no photoelectrons are emitted from that metal surface (whatever may be the intensity of incident light).

(3) The stopping potential is the value of the retarding potential difference that is just sufficient to stop the most energetic photoelectrons emitted from reaching the collector so that the photoelectric current in a photocell reduces to zero.

[Note : The threshold wavelength λ₀ = c/v₀, where c is the speed of light in free space and v is the threshold frequency for the metal.]

From Einstein’s photoelectric equation,
hv = hv₀ + eV₀
v = v₀
hv₀ = hv₀ + eV₀
v₀ = 0
∴ Stopping potential = 0

These observations have two implications: 

(i) The maximum kinetic energy of the photoelectrons varies linearly with the frequency of incident radiation, but is independent of its intensity. 

(ii) For a frequency n of incident radiation, lower than the cut-off frequency n₀, no photoelectric emission is possible even if the intensity is large. This minimum, cut-off frequency n₀, is called the threshold frequency. It is different for different metals. 

Different photosensitive materials respond differently to light. Selenium is more sensitive than zinc or copper. The same photosensitive substance gives different response to light of different wavelengths. For example, ultraviolet light gives rise to photoelectric effect in copper while green or red light does not. 

For the given differential equation, we know that the highest order derivative is d⁴y/dx⁴ and its order is 4

Hence, the order is 4 and the degree is not defined since it has a term cos (d³y/dx³)