Discussion
Home ‣ General Knowledge ‣ Physics Comments
- Question
For a certain reaction,DGq = -45 kJ/mol and DHq= -90 kJ/mol at 0°C. What is the minimum temperature at which the reaction will become spontaneous, ifDHq and DSq are independent of temperature?
Options- A. 273 K
- B. 298 K
- C. 546 K
- D. 596 K
- Correct Answer
- 546 K
ExplanationT = 273 °K
Using the formula,
DGq = DHq ?TDS
-45 = -90 ?273 DS
DS = 0.164
Now since DHq and DSq are independent,T2= DH/DS = 45/0.164 = 273°K
Required Temp = 273 + 273 = 546°K
- 1. Which of the following is/are state function / functions? 1. q + w 2. q 3. w 4. H -TS Select the correct answer using the code given below.
Options- A. 1 and 4 only
- B. 1, 2 and 4
- C. 2, 3 and 4
- D. 1 only Discuss
- 2. An electron and a proton starting from rest get accelerated through potential difference of 100kV. The final speeds of the electron and the proton are Ve and Vp respectively. Which of the following relations is correct?
Options- A. Ve > Vp
- B. Ve < Vp
- C. Ve = Vp
- D. Cannot be determined Discuss
- 3. If the wavelengths corresponding to ultraviolet, visible and infrared radiations are given as lUV, lVIS and lIR respectively, then which of the following gives the correct relationship among these wavelengths?
Options- A. lUV < lIR < lVIS
- B. lUV > lVIS > lIR
- C. lUV > lIR > lVIS
- D. lUV < lVIS < lIR Discuss
- 4. Two identical solid pieces, one of gold and other of silver, when immersed completely in water exhibit equal weights. When weighed in air (given that density of gold is greater than that of silver)
Options- A. the gold piece will weigh more
- B. the silver piece will weighmore
- C. both silver and gold pieces weigh equal
- D. weighing will depend on their masses Discuss
- 5. Light travels in a straight line (rectilinear propagation of light). This statement does hold if the medium of travel for light is
Options- A. of variable refractive index
- B. made up of slabs of different refractive indices
- C. homogeneous and transparent
- D. inhomogeneous and transparent Discuss
- 6. In spherical polar coordinates (l, q, a), q denotesthe polar angle around z-axis and a denotes the azimuthal angle raised from x-axis . Then the y-component of P is given by
Options- A. Psinq sina
- B. Psinq cosa
- C. Pcosq sina
- D. Pcosq cosa Discuss
- 7. For an ideal gas, which one of the following statements does not hold true?
Options- A. The speed of all gas molecules is same
- B. The kinetic energies of all gas molecules are not same
- C. The potential energy of the gas molecules is zero
- D. There is no interactive force between the molecules. Discuss
- 8. The Hooke's law is valid for
Options- A. only proportional region of the stress strain curve
- B. entire stress strain curve
- C. entire elastic region of the stress strain curve
- D. elastic as well as plastic region of the stress strain curve Discuss
- 9. Which one of the following is the correct sequence of passage of light in a compound microscope?
Options- A. Condenser -Objective lens -Eye -piece -Body tube
- B. Objective lens -Condenser -Body tube -Eye piece
- C. Condenser -Objective lens -Body tube -Eyepiece
- D. Eyepiece -Objective lens -Body tube -Mirror Discuss
- 10. Which of the following device is used to measure humidity?
Options- A. Hydrometer
- B. Hygrometer
- C. Psycho Meter
- D. Anemometer Discuss
Physics problems
Search Results
Correct Answer: 1 and 4 only
Explanation:
Q and w are path functions while q+w i.e. H, enthalpy is state function. Similarly, H-TS i.e. G, Gibbs free energy is state function.
Correct Answer: Ve > Vp
Explanation:
Both when accelerated through a potential difference of 100KV, they will have the same energy. The mass of the electron is less than the mass of a proton, hence it will move faster(momentum).
Correct Answer: lUV < lVIS < lIR
Explanation:
Infrared radiation, what we experience as heat when we hold our hand near a warm object, is somewhat longer wavelengths than visible light. Visible light is simply electromagnetic radiation in a range of wavelengths that our eyes are sensitive to. Visible wavelengths range from 0.0007 milimeters for red light, through orange, yellow, green, and blue, to 0.0004 milimeters for violet light. Ultraviolet is shorter wavelengths than violet.
Longer the wavelength,lower the energy
Correct Answer: the silver piece will weighmore
Explanation:
As it is said that density of gold is greater than that of density of silver, so silver occupies a greater volume than gold. So it has more upthrust from the water, although they both show the same weight under water, there is more silver present. Hence silver piece will weigh more.
Correct Answer: homogeneous and transparent
Explanation:
In vacuum and in homogeneous, transparent media, such as air, water, and glass, light moves in a straight line. When light encounters a boundary between two different transparent media, some light is reflected and some moves from the first into the second medium.
Correct Answer: Psinq sina
Explanation:
The Cartesian Coordinates can be retrieved from spherical coordinates (l,q,a) by:
X = r.sinq.cosa
Y = r.sinq.sina
Z = r.sinq
Using the same we get for P,
Y = P.sinq.sina
Correct Answer: The speed of all gas molecules is same
Explanation:
In an ideal gas, at any particular time, different particles in the gas have different speeds and hence different kinetic energies. This assumption is reasonable because as the particles collide, we expect their speed to change. Even if initial speed of all the particles was same, the molecular collisions will disrupt this uniformity.Hence statement 1 is incorrect and 2 is correct.
Correct Answer: only proportional region of the stress strain curve
Explanation:
Hooke's law states that within the elastic limit, stress developed is directly proportional to the strain produced in a body.Hooke?s law is valid only in the linear part of stress-strain curve. Hence, statement 1 is correct.
Correct Answer: Condenser -Objective lens -Body tube -Eyepiece
Correct Answer: Hygrometer
Comments
There are no comments.More in General Knowledge:
Programming
Copyright ©CuriousTab. All rights reserved.