Physics

This is a multiple choice answer as classified in NCERT Exemplar

(a), (b), (d) When the rod is hammered the external work is done on the rod which increases its temperature.

Heat is transferred to the gas in the small container by big reservoir at temperature T₂

As the weight is added to the cylinder arrangement in the form of external pressure so it cannot reversed.

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation- according to the relation V=e-Ir and I=e/r+R

The graphical relation between voltage and resistance.

This is a multiple choice answer as classified in NCERT Exemplar

(b) Let us assume that T₁, T₂T₃

According to questions there is no loss of heat in the surroundings

Heat lost by M₃ = heat gained by M₁+ heat gained by M₂

M₃s (T₃-T)= M₁s (T-T₁)+M₂s (T-T₂)

T [M₁+M₂+M₃]= M₃T₃+M₁T₁+M₂T₂

T = $\frac{M_1{T}_1+M_2{T}_2+M_3{T}_3}{M_1+M_2+M_3}$

This is a multiple choice answer as classified in NCERT Exemplar

(a) Container A is isothermal and container B is adiabatic

For isothermal process P₁V₁=P₂V₂

P_o (2V_o)= P₂ (V_o)

P₂= 2P_o

for adiabatic process

P₁V₁^y= P₂V₂^y

P_o (2V_o)^y=P₂ (V_o)^y

P₂= ( $\frac{2V_o}{V_o}$ )^yP_o= 2^yP_o

Hence ratio of final pressure = $\frac{2^{\gamma }{P}_o}{2P_o}=2^{\gamma -1}$

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Explanation- If the value of R is increased, the current through the wire will decrease which in turn decreases the potential difference across AB, and  hence potential gradient (k) across AB decreases.
Since, at neutral point, for given emf of cell, l increases as potential gradient (k) across AB has decreased because E' = kl
Thus, with the increase of l, which will result in increase in balance length. So, jockey J will shift towards B

This is a Short Answer Type Questions as classified in NCERT Exemplar

Explanation – power consumed through wire is P=V^2/R =I²R . for transmitting the power there are two types either current is large or voltage is less or vice versa. But when current in the circuit is higher then power loss is also higher . so we transmit the power through high voltage circuits.

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(b) Work done ABCD = area of rectangle ABCDA

= AB $*BC$ = (3V_o-V_o) $*$ (2p_o-p_o)

= 2V_{0 $*$} P_o= 2p_oV_o

And work done by the gas =- 2p_oV_o

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Explanation- Alloys are used for making standard resistance coil because they have low temperature coefficient of resistance with less temperature sensitivity. The alloys also have high resistivity and hence high resistance, because for given length and cross-section area of conductor .

This is a multiple choice answer as classified in NCERT Exemplar

(c) As we know PV =constant

Hence we can say that gas is going through an isothermal process.

Clearly from the graph that between process 1 and 2 temperature is constant and the gas expands and pressure decreases. So density of 2 is less than 1 so option ii