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- Question
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
- Correct Answer
- lUV < lVIS < lIR
ExplanationInfrared 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
- 1. 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
- 2. 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
- 3. Liquids and gases never show
Options- A. diamagnetic property
- B. paramagnetic property
- C. ferromagnetic property
- D. electromagnetic property Discuss
- 4. The energy of a photon, whose momentum is 10 MeV/c, where c is the speed of light, is given by
Options- A. 10 MeV
- B. 100 MeV
- C. 1 MeV
- D. 0.1 MeV Discuss
- 5. In total internal reflection, the light travel from
Options- A. rarer to denser medium and it occurs with no loss of intensity
- B. denser to rarer medium and it occurs with no loss of intensity
- C. rarer to denser medium and it occurs with loss of intensity
- D. denser to rarer medium and it occurs with loss of intensity Discuss
- 6. 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
- 7. 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
- 8. 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 Discuss
- 9. 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
- 10. 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
Physics problems
Search Results
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: ferromagnetic property
Explanation:
On the basis of magnetic properties, substances are classified into three groups namely diamagnetic, paramagnetic and ferromagnetic.
As solids diffuse and reorder very slowly under ambient conditions, the net, directionally dependent (anisotropic) magnetic moment can persist. Conversely, liquids and gases freely tumble and reorder: water rearranges every few pico seconds (10^12 times per second).
Hence liquids and gases can never show ferromagnetic properties.
Correct Answer: 10 MeV
Explanation:
A photon?s relativistic momentum is given by the equation,E = pc where p is the momentum.
P = 10 MeV/c
So, E = 10 MeV
Correct Answer: denser to rarer medium and it occurs with no loss of intensity
Explanation:
According to wave theories, for Total internal reflection tohappen: Light must travel from denser medium to rarer medium. Angle of incidence should be greater than critical angle. As in case of TIR, the image is perfectly clear, it implies that there has been no loss of intensity.
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: 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: 546 K
Explanation:
T = 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
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.
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