The expression, ∆G = nRT. ln(P2/P1), gives the free energy change (A) With pressure changes at constant temperature (B) Under reversible isothermal volume change (C) During heating of an ideal gas (D) During cooling of an ideal gas

The expression, ∆G = nRT. ln(P2/P1), gives the free energy change (A) With pressure changes at constant temperature
(B) Under reversible isothermal volume change
(C) During heating of an ideal gas
(D) During cooling of an ideal gas
by

1 Answer

Answer :

(A) With pressure changes at constant temperature
by

Related questions

The expression for entropy change given by, ΔS = - nR ln (P2/P1), holds good for (A) Expansion of a real gas (B) Reversible isothermal volume change (C) Heating of an ideal gas (D) Cooling of a real gas

Description : The expression for entropy change given by, ΔS = - nR ln (P2/P1), holds good for (A) Expansion of a real gas (B) Reversible isothermal volume change (C) Heating of an ideal gas (D) Cooling of a real gas

Last Answer : (B) Reversible isothermal volume change

The expression, nRT ln(P1/P2), is for the __________of an ideal gas. (A) Compressibility (B) Work done under adiabatic condition (C) Work done under isothermal condition (D) Co-efficient of thermal expansion

Description : The expression, nRT ln(P1/P2), is for the __________of an ideal gas. (A) Compressibility (B) Work done under adiabatic condition (C) Work done under isothermal condition (D) Co-efficient of thermal expansion

Last Answer : C) Work done under isothermal condition

The expression for entropy change given by, ΔS = nR ln (V2/V1) + nCvln (T2/T1) is valid for (A) Reversible isothermal volume change (B) Heating of a substance (C) Cooling of a substance (D) Simultaneous heating and expansion of an ideal gas

Description : The expression for entropy change given by, ΔS = nR ln (V2/V1) + nCvln (T2/T1) is valid for (A) Reversible isothermal volume change (B) Heating of a substance (C) Cooling of a substance (D) Simultaneous heating and expansion of an ideal gas

Last Answer : (D) Simultaneous heating and expansion of an ideal gas

To obtain integrated form of Clausius-Clapeyron equation, ln (P2/P1) = (∆HV/R) (1/T1- 1/T2) from the exact Clapeyron equation, it is assumed that the (A) Volume of the liquid phase is negligible compared to that of vapour phase (B) Vapour phase behaves as an ideal gas (C) Heat of vaporisation is independent of temperature (D) All (A), (B) & (C)

Description : To obtain integrated form of Clausius-Clapeyron equation, ln (P2/P1) = (∆HV/R) (1/T1- 1/T2) from the exact Clapeyron equation, it is assumed that the (A) Volume of the liquid phase is negligible compared to ... gas (C) Heat of vaporisation is independent of temperature (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Which of the following is the Ideal gas law (equation)?  A. V/T = K  B. V= k*(1/P)  C. P1/T1 = P2/T2  D. PV = nRT

Description : Which of the following is the Ideal gas law (equation)?  A. V/T = K  B. V= k*(1/P)  C. P1/T1 = P2/T2  D. PV = nRT

Last Answer : PV = nRT

The expression for entropy change, ΔS = n Cp. ln (T2/T1), is valid for the __________ of a substance. (A) Simultaneous pressure & temperature change (B) Heating (C) Cooling (D) Both (B) and (C)

Description : The expression for entropy change, ΔS = n Cp. ln (T2/T1), is valid for the __________ of a substance. (A) Simultaneous pressure & temperature change (B) Heating (C) Cooling (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to the __________ mean of P1 and P2.(where, P1 and P2 are initial and final pressures respectively) (A) Logarithmic (B) Arithmetic (C) Geometric (D) Harmonic

Description : A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to ... final pressures respectively) (A) Logarithmic (B) Arithmetic (C) Geometric (D) Harmonic

Last Answer : (C) Geometric

There are 1.36 kg of gas, for which R = 377 J/kg.k and k = 1.25, that undergo a nonflow constant volume process from p1 = 551.6 kPa and t1 = 60°C to p2 = 1655 kPa. During the process the gas is internally stirred and there are also added 105.5 kJ of heat. Determine t2. (Formula: T2= T1p2/ p1)  a. 999 K  b. 888 K  c. 456 K  d. One of the above

Description : There are 1.36 kg of gas, for which R = 377 J/kg.k and k = 1.25, that undergo a nonflow constant volume process from p1 = 551.6 kPa and t1 = 60°C to p2 = 1655 kPa. During the process the gas is internally stirred and ... (Formula: T2= T1p2/ p1)  a. 999 K  b. 888 K  c. 456 K  d. One of the above

Last Answer : 999 K

What horse power is required to isothermally compress 800 ft^3 of Air per minute from 14.7 psia to 120 psia?  A. 28 hp  B.108 hp  C.256 hp  D.13900 hp Formula: W= p1V1 ln (p1/p2) Power = dW / dt

Description : What horse power is required to isothermally compress 800 ft^3 of Air per minute from 14.7 psia to 120 psia?  A. 28 hp  B.108 hp  C.256 hp  D.13900 hp Formula: W= p1V1 ln (p1/p2) Power = dW / dt

Last Answer : 108 hp

What is the resulting pressure when one pound of air at 15 psia and 200 ˚F is heated at constant volume to 800 ˚F?  A.15 psia  B. 28.6 psia  C. 36.4 psia.  D. 52.1 psia Formula : T1/p1 = T2/p2 p2= p1T2 / T1

Description : What is the resulting pressure when one pound of air at 15 psia and 200 ˚F is heated at constant volume to 800 ˚F?  A.15 psia  B. 28.6 psia  C. 36.4 psia.  D. 52.1 psia Formula : T1/p1 = T2/p2 p2= p1T2 / T1

Last Answer : 28.6 psia

. The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is (A) R loge 4 (B) R log10 4 (C) Cv log10 4 (D) Cv loge 4

Description : . The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is (A) R loge 4 (B) R log10 4 (C) Cv log10 4 (D) Cv loge 4

Last Answer : (A) R loge 4

. The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is (A) R loge 4 (B) R log10 4 (C) Cv log10 4 (D) Cv loge 4

Description : . The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is (A) R loge 4 (B) R log10 4 (C) Cv log10 4 (D) Cv loge 4

Last Answer : (A) R loge 4

What happens in a reversible adiabatic expansion process? (A) Heating takes place (B) Cooling takes place (C) Pressure is constant (D) Temperature is constant

Description : What happens in a reversible adiabatic expansion process? (A) Heating takes place (B) Cooling takes place (C) Pressure is constant (D) Temperature is constant

Last Answer : (B) Cooling takes place

What happens in a reversible adiabatic compression? (A) Heating occurs (B) Cooling occurs (C) Pressure is constant (D) Temperature is constant

Description : What happens in a reversible adiabatic compression? (A) Heating occurs (B) Cooling occurs (C) Pressure is constant (D) Temperature is constant

Last Answer : A) Heating occurs

Which of the following statements is TRUE for an ideal gas, but not for a real gas?  A. PV = nRT  B. An increase in temperature causes an increase in the kinetic energy of the gas  C. The total volume of molecules on a gas is nearly the same as the volume of the gas as a whole  D. No attractive forces exists between the molecule of a gas

Description : Which of the following statements is TRUE for an ideal gas, but not for a real gas?  A. PV = nRT  B. An increase in temperature causes an increase in the kinetic energy of the gas  C. The ... same as the volume of the gas as a whole  D. No attractive forces exists between the molecule of a gas

Last Answer : PV = nRT

Which of the following processes are thermodynamically reversible  (a) throttling  (b) free expansion  (c) constant volume and constant pressure  (d) hyperbolic and pV = C  (e) isothermal and adiabatic.

Description : Which of the following processes are thermodynamically reversible  (a) throttling  (b) free expansion  (c) constant volume and constant pressure  (d) hyperbolic and pV = C  (e) isothermal and adiabatic.

Last Answer : Answer : e

For the reversible isothermal expansion of one mole of an ideal gas at 300 K, from a volume of `10 dm^(3)` to `20 dm^(3), Delta H` is -

Description : For the reversible isothermal expansion of one mole of an ideal gas at 300 K, from a volume of `10 dm^(3)` to `20 dm^(3), Delta H` is -

Last Answer : For the reversible isothermal expansion of one mole of an ideal gas at 300 K, from a volume of `10 dm^(3)` to ` ... . `-1.73 KJ` C. `3.46 KJ` D. Zero

Pick out the correct statement. (A) The available energy in an isolated system for all irreversible (real) processes decreases (B) The efficiency of a Carnot engine increases, if the sink temperature is decreased (C) The reversible work for compression in non-flow process under isothermal condition is the change in Helmholtz free energy (D) All (A), (B) and (C)

Description : Pick out the correct statement. (A) The available energy in an isolated system for all irreversible (real) processes decreases (B) The efficiency of a Carnot engine increases, if the sink temperature is decreased ... condition is the change in Helmholtz free energy (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Q No: 251 In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is A. [(100 + P1)/(100 – P2)] V1 B. [(100 – P1)/(100 + P2)] V1 C. [(100 – P1)/(100 – P2)] V1 D. [(100 + P2)/(100 – P1)] V1

Description : Q No: 251 In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is A. [(100 + P1)/(100 – P2)] V1 B. [(100 – P1)/(100 + P2)] V1 C. [(100 – P1)/(100 – P2)] V1 D. [(100 + P2)/(100 – P1)] V1

Last Answer : ANS: C

According to the American Society of Anesthesiology Physical Status Classification System, a patient with severe systemic disease that is not incapacitating is noted to have physical status classification a) P3 Classification P3 patients are those who have compensated heart failure, cirrhosis, or poorly controlled diabetes, for example. b) P4 Classification P4 patients have an incapacitating systemic disease that is a constant threat to life. c) P1 Classification P1 refers to a normal healthy patient d) P2 Classification P2 reflects a patient with mild systemic disease

Description : According to the American Society of Anesthesiology Physical Status Classification System, a patient with severe systemic disease that is not incapacitating is noted to have physical status ... normal healthy patient d) P2 Classification P2 reflects a patient with mild systemic disease

Last Answer : a) P3 Classification P3 patients are those who have compensated heart failure, cirrhosis, or poorly controlled diabetes, for example.

Which of the following is Clausius-Clapeyron Equation for vaporisation of an ideal gas under the condition that the molar volume of liquid is negligible compared to that of the vapor? (A) d ln p/dt = Hvap/RT2 (B) d ln p/dt = RT2/Hvap (C) dp/dt = RT2/Hvap (D) dp/dt = Hvap/RT2

Description : Which of the following is Clausius-Clapeyron Equation for vaporisation of an ideal gas under the condition that the molar volume of liquid is negligible compared to that of the vapor? (A) d ln p/dt = Hvap/RT2 (B) d ln p/dt = RT2/Hvap (C) dp/dt = RT2/Hvap (D) dp/dt = Hvap/RT2

Last Answer : (A) d ln p/dt = Hvap/RT2

The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition. (A) Internal energy (B) Enthalpy (C) Gibbs free energy (D) Helmholtz free energy

Description : The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition. (A) Internal energy (B) Enthalpy (C) Gibbs free energy (D) Helmholtz free energy

Last Answer : (C) Gibbs free energy

On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)s and the slope of the reversible isothermal line (∂P/∂V)T are related as (where, y = Cp/Cv) (A) (∂P/∂V)S = (∂P/∂V)T (B) (∂P/∂V)S = [(∂P/∂V)T]Y (C) (∂P/∂V)S = y(∂P/∂V)T (D) (∂P/∂V)S = 1/y(∂P/∂V)T

Description : On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)s and the slope of the reversible isothermal line ... Y (C) (∂P/∂V)S = y(∂P/∂V)T (D) (∂P/∂V)S = 1/y(∂P/∂V)T

Last Answer : (C) (∂P/∂V)S = y(∂P/∂V)T

For an isothermal reversible compression of an ideal gas (A) Only ΔE = 0 (B) Only ΔH =0 (C) ΔE = ΔH = 0 (D) dQ = dE

Description : For an isothermal reversible compression of an ideal gas (A) Only ΔE = 0 (B) Only ΔH =0 (C) ΔE = ΔH = 0 (D) dQ = dE

Last Answer : C) ΔE = ΔH = 0

Clausius-Clapeyron Equation gives accurate result, when the (A) Vapour pressure is relatively low and the temperature does not vary over wide limits (B) Vapour obeys the ideal gas law and the latent heat of vaporisation is constant (C) Volume in the liquid state is negligible compared with that in the vapour state (D) All (A), (B) and (C)

Description : Clausius-Clapeyron Equation gives accurate result, when the (A) Vapour pressure is relatively low and the temperature does not vary over wide limits (B) Vapour obeys the ideal gas law and the latent heat of ... is negligible compared with that in the vapour state (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Entropy of a substance remains constant during a/an __________ change. (A) Reversible isothermal (B) Irreversible isothermal (C) Reversible adiabatic (D) None of these

Description : Entropy of a substance remains constant during a/an __________ change. (A) Reversible isothermal (B) Irreversible isothermal (C) Reversible adiabatic (D) None of these

Last Answer : (C) Reversible adiabatic

The ideal gas equation is A. PV = constant B. PT = constant C. V⁄T D. PV = nRT

Description : The ideal gas equation is A. PV = constant B. PT = constant C. V⁄T D. PV = nRT

Last Answer : PV = nRT

Under standard conditions (A) The free energy change ∆G°, is equal to 0 (B) The standard free energy change ∆G, is equal to 0 (C) The free energy change, ∆G°, is equal to the standard free energy change, ∆G° (D) Keq is equal to 1

Description : Under standard conditions (A) The free energy change ∆G°, is equal to 0 (B) The standard free energy change ∆G, is equal to 0 (C) The free energy change, ∆G°, is equal to the standard free energy change, ∆G° (D) Keq is equal to 1

Last Answer : C

The expression for the work done for a reversible polytropic process can be used to obtain the expression for work done for all processes, except reversible __________ process. (A) Isobaric (B) Isothermal (C) Adiabatic (D) None of these

Description : The expression for the work done for a reversible polytropic process can be used to obtain the expression for work done for all processes, except reversible __________ process. (A) Isobaric (B) Isothermal (C) Adiabatic (D) None of these

Last Answer : (B) Isothermal

In an isothermal process on an ideal gas, the pressure increases by 0.5 percent. The volume decreases by about __________ percent. (A) 0.25 (B) 0.5 (C) 0.75 (D) 1

Description : In an isothermal process on an ideal gas, the pressure increases by 0.5 percent. The volume decreases by about __________ percent. (A) 0.25 (B) 0.5 (C) 0.75 (D) 1

Last Answer : (B) 0.5

Change in internal energy in a closed system is equal to heat transferred if the reversible process takes place at constant  (a) pressure  (b) temperature  (c) volume  (d) internal energy  (e) entropy.

Description : Change in internal energy in a closed system is equal to heat transferred if the reversible process takes place at constant  (a) pressure  (b) temperature  (c) volume  (d) internal energy  (e) entropy.

Last Answer : Answer : c

Change in enthalpy in a closed system is equal to heat transferred if the reversible process takes place at constant  (a) pressure  (b) temperature  (c) volume  (d) internal energy  (e) entropy.

Description : Change in enthalpy in a closed system is equal to heat transferred if the reversible process takes place at constant  (a) pressure  (b) temperature  (c) volume  (d) internal energy  (e) entropy.

Last Answer : Answer : a

What is the name given to the equation PV=nRT? w) law of partial pressure x) ideal gas equation y) quadratic equation z) Raoult's equation

Description : What is the name given to the equation PV=nRT? w) law of partial pressure x) ideal gas equation y) quadratic equation z) Raoult's equation

Last Answer : ANSWER: X -- IDEAL GAS EQUATION

Pick out the correct statement. (A) Like internal energy and enthalpy, the absolute value of standard entropy for elementary substances is zero (B) Melting of ice involves increase in enthalpy and a decrease in randomness (C) The internal energy of an ideal gas depends only on its pressure (D) Maximum work is done under reversible conditions

Description : Pick out the correct statement. (A) Like internal energy and enthalpy, the absolute value of standard entropy for elementary substances is zero (B) Melting of ice involves increase in enthalpy and ... of an ideal gas depends only on its pressure (D) Maximum work is done under reversible conditions

Last Answer : (D) Maximum work is done under reversible conditions

Pick out the wrong statement: (A) The expansion of a gas in vacuum is an irreversible process (B) An isometric process is a constant pressure process (C) Entropy change for a reversible adiabatic process is zero (D) Free energy change for a spontaneous process is negative

Description : Pick out the wrong statement: (A) The expansion of a gas in vacuum is an irreversible process (B) An isometric process is a constant pressure process (C) Entropy change for a reversible adiabatic process is zero (D) Free energy change for a spontaneous process is negative

Last Answer : (B) An isometric process is a constant pressure process

For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant(A) Is independent of pressure(B) Increases with pressure(C) Decreases with pressure(D) Increases /decreases with pressure depending on the stoichiometric co￾efficients of the reaction

Description : For an ideal gas mixture undergoing a reversible gaseous phase chemical reaction, the equilibrium constant (A) Is independent of pressure (B) Increases with pressure (C) Decreases with pressure (D) Increases /decreases with pressure depending on the stoichiometric co￾efficients of the reaction

Last Answer : (B) Increases with pressure

Which of the following is not a reversible process? (A) Expansion of an ideal gas against constant pressure (B) Atmospheric pressure vaporisation of water at 100°C (C) Solution of NaCl in water at 50°C (D) None of these

Description : Which of the following is not a reversible process? (A) Expansion of an ideal gas against constant pressure (B) Atmospheric pressure vaporisation of water at 100°C (C) Solution of NaCl in water at 50°C (D) None of these

Last Answer : C) Solution of NaCl in water at 50°C

Two lines L1 and L2 having Parametric equations are P1=[3 4 7]+u[2 2 -6] and P2=[15 -2]+u[1 4 2]. Tangent vector for line L1 a.2i+2j-6k b.2i+2j+6k c.2i-2j-6k d.6-2j-2k

Description : Two lines L1 and L2 having Parametric equations are P1=[3 4 7]+u[2 2 -6] and P2=[15 -2]+u[1 4 2]. Tangent vector for line L1 a.2i+2j-6k b.2i+2j+6k c.2i-2j-6k d.6-2j-2k

Last Answer : a.2i+2j-6k

Two lines are parallel when a.P1 X P2=0 b.P1 . P2=0 c.P1 = P2 d.P1+ P2=0

Description : Two lines are parallel when a.P1 X P2=0 b.P1 . P2=0 c.P1 = P2 d.P1+ P2=0

Last Answer : a.P1 X P2=0

Find coordinates of points on line having end points P1(3,5,8) and P2 (6,4,3) at u=0.25 a.[3.75 4.25 6.25] b.[3.25 4.25 6.25] c.[3.75 4.75 6.75] d.[4.25 3.75 6.25]

Description : Find coordinates of points on line having end points P1(3,5,8) and P2 (6,4,3) at u=0.25 a.[3.75 4.25 6.25] b.[3.25 4.25 6.25] c.[3.75 4.75 6.75] d.[4.25 3.75 6.25]

Last Answer : c.[3.75 4.75 6.75]

Find the tangent vector of line having end points P1(3,5,8) and P2 (6,4,3) a.3i+j-5k b.3i-j-5k c.3i-j+5k d.-3i-j-5k

Description : Find the tangent vector of line having end points P1(3,5,8) and P2 (6,4,3) a.3i+j-5k b.3i-j-5k c.3i-j+5k d.-3i-j-5k

Last Answer : b.3i-j-5k

Write parametric equation of line having end points P1(3,5,8) and P2 (6,4,3). a.[3 5 8]+u[3 -1 -5] b.[3 5 8]+u[3 1 5] c.[3 8 5]+u[3 -1 -5] d.[3 5 8]+u[-3 1 5]

Description : Write parametric equation of line having end points P1(3,5,8) and P2 (6,4,3). a.[3 5 8]+u[3 -1 -5] b.[3 5 8]+u[3 1 5] c.[3 8 5]+u[3 -1 -5] d.[3 5 8]+u[-3 1 5]

Last Answer : a.[3 5 8]+u[3 -1 -5]

In a 2-D CAD package, clockwise circular arc of radius, 5, specified from P1 (15,10)to P2 (10,15)will have its center at a.(10, 10) b.(15, 10) c.(15, 15) d.(10, 15)

Description : In a 2-D CAD package, clockwise circular arc of radius, 5, specified from P1 (15,10)to P2 (10,15)will have its center at a.(10, 10) b.(15, 10) c.(15, 15) d.(10, 15)

Last Answer : a.(10, 10)

The molecular formula of phosphorus is (a) P1 (b) P2 (c) P3 (d) P4

Description : The molecular formula of phosphorus is (a) P1 (b) P2 (c) P3 (d) P4

Last Answer : Ans:(d)

A signal is measured at two different points. The power is P1 at the first point and P2 at the second point. The dB is 0. This means________. A) P2 is zero B) P2 equals P1 C) P2 is much larger than P1 D) P2 is much smaller than P1

Description : A signal is measured at two different points. The power is P1 at the first point and P2 at the second point. The dB is 0. This means________. A) P2 is zero B) P2 equals P1 C) P2 is much larger than P1 D) P2 is much smaller than P1

Last Answer : P2 equals P1

The unit vector to the points p1(0,1,0), p2(1,0,1), p3(0,0,1) is a) (-j – k)/1.414 b) (-i – k)/1.414 c) (-i – j)/1.414 d) (-i – j – k)/1.414

Description : The unit vector to the points p1(0,1,0), p2(1,0,1), p3(0,0,1) is a) (-j – k)/1.414 b) (-i – k)/1.414 c) (-i – j)/1.414 d) (-i – j – k)/1.414

Last Answer : a) (-j – k)/1.414

Find a vector normal to a plane consisting of points p1(0,1,0), p2(1,0,1) and p3(0,0,1) a) –j – k b) –i – j c) –i – k d) –i – j – k

Description : Find a vector normal to a plane consisting of points p1(0,1,0), p2(1,0,1) and p3(0,0,1) a) –j – k b) –i – j c) –i – k d) –i – j – k

Last Answer : a) –j – k

Find out the price elasticity in the following example : Price Demand 5(P1) 10(Q1) 4(P2) 15(Q2) (a) – 2.5 (b) + 3.5 (c) + 4.0 (d) + 2.5

Description : Find out the price elasticity in the following example : Price Demand 5(P1) 10(Q1) 4(P2) 15(Q2) (a) – 2.5 (b) + 3.5 (c) + 4.0 (d) + 2.5

Last Answer : (a) – 2.5

A short column (30 cm × 20 cm) carries a load P1 at 4 cm on one side and another load P2at 8 cm on the other side along a principal section parallel to longer dimension. If the extreme intensity on either side is same, the ratio of P1 to P2 will be (A) 2/3 (B) 3/2 (C) 8/5 (D) 5/8

Description : A short column (30 cm 20 cm) carries a load P1 at 4 cm on one side and another load P2at 8 cm on  the other side along a principal section parallel to longer dimension. If the extreme intensity on  either side is same, the ... to P2 will be  (A) 2/3  (B) 3/2  (C) 8/5  (D) 5/8 

Last Answer : (C) 8/5 

If f1 and f2 are the distances from the optical centre of a convex lens of focal length to conjugate two points P1 and P2 respectively, the following relationship holds good (A) f = f1 + f2 (B) f = ½ (f1 + f2) (C) 1/f = 1/f1 + 1/f2 (D) None of these

Description : If f1 and f2 are the distances from the optical centre of a convex lens of focal length to conjugate two points P1 and P2 respectively, the following relationship holds good (A) f = f1 + f2 (B) f = ½ (f1 + f2) (C) 1/f = 1/f1 + 1/f2 (D) None of these

Last Answer : (C) 1/f = 1/f1 + 1/f2