- Ais zero.
- Bincreases from centre to the surface.
- Cdecreases from centre to the surface.
- Dremains constant from centre to the surface.
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In determining the temperature of a distant star, one makes use of
|
(a) Kirchhoff's law |
(b) Stefan's law |
|
(c) Wien's displacement law |
(d) None of these |
A conductor in the form of a right angle ABC with AB = 3 cm and BC = 4 cm carries a current of 10 A. There is a uniform magnetic field of 5 T perpendicular to the plane of the conductor. The force on the conductor will be
|
(a) 1.5 N |
(b) 2.0 N |
(c) 2.5 N |
(d) 3.5 N |
Kα wavelength emitted by an atom of atomic number Z = 11 is λ. Find the atomic number for an atom that emits Kα radiation with wavelength 4l
|
(a) Z = 6 |
(b) Z = 4 |
(c) Z = 11 |
(d) Z = 44 |
An electric current passes through a long straight wire. At a distance 5 cm from the wire, The magnetic field is B. The field at 20 cm from the wire would be
|
(a) |
(b) |
(c) |
(d) |
A man wearing glasses of focal length +1m cannot clearly see beyond 1m:
For production of characteristic
X-rays, the electron transition is
|
(a) n = 2 to n = 1 |
(b) n = 3 to n = 2 |
(c) n = 3 to n = 1 |
(d) n = 4 to n = 2 |
Figure represents the graph of photo current I versus applied voltage (V). The maximum energy of the emitted photoelectrons is

|
(a) 2eV |
(b) 4 eV |
(c) 0 eV |
(d) 4 J |
The activity of a radioactive sample is measured as 9750 counts per minute at t = 0 and as 975 counts per minute at t = 5 minutes. The decay constant is approximately
|
(a) 0.230 per minute |
(b) 0.461 per minute |
|
(c) 0.691 per minute |
(d) 0.922 per minute |