Explanation:
A paramagnetic material is placed in a magnetic field.
Þ If the magnetic field is increased, the magnetization is increased.
$\therefore\text{Magnetiazation}\overrightarrow{\text{I}}=\frac{\text{Magnetic Moment}}{\text{volume}}=\frac{\overrightarrow{\text{M}}}{\text{V}}$
Þ If the temperature is increaed, the magnetization is decreased.
Because susceptibility of a paramagnetic substance is inversely proportional to the absolute temperarue.
$\text{X}=\frac{\text{C}}{\text{T}}$
after curie temperature susceptibility varies with temperature as $\text{X}=\frac{\text{C}^1}{\text{T}-\text{T}_\text{C}}$
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A photodetector is made from a semiconductor In 0.53Ga 0.47As with Eg = 0.73 eV. What is the maximum wavelength, which it can detect
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(a) 1000 nm |
(b) 1703 nm |
(c) 500 nm |
(d) 173 nm |
An isolated solid metallic sphere is given +Q charge. The charge will be distributed on the sphere
|
(a) Uniformly but only on surface |
|
(b) Only on surface but non-uniformly |
|
(c) Uniformly inside the volume |
|
(d) Non-uniformly inside the volume |
Two capacitors of capacitance 2 μF and 3μF are joined in series. Outer plate first capacitor is at 1000 volt and outer plate of second capacitor is earthed (grounded). Now the potential on inner plate of each capacitor will be
|
(a) 700 Volt |
(b) 200 Volt |
(c) 600 Volt |
(d) 400 Volt |
For a triode 
kilo ohm and 
milli mho. If the load resistance is double of plate resistance, then the value of voltage gain will be
|
(a) 10 |
(b) 20 |
(c) 15 |
(d) 30 |
Unpolarized light falls on two polarizing sheets placed one on top of the other. What must be the angle between the characteristic directions of the sheets if the intensity of the final transmitted light is one-third the maximum intensity of the first transmitted beam
|
(a) 75° |
(b) 55° |
(c) 35° |
(d) 15° |
Every series of hydrogen spectrum has an upper and lower limit in wavelength. The spectral series which has an upper limit of wavelength equal to 18752 Å is (Rydberg constant 
per metre)
|
(a) Balmer series |
(b) Lyman series |
(c) Paschen series |
(d) Pfund series |
Assertion : Acceleration of a magnet falling through a long solenoid decreases.
Reason : The induced current produced in a circuit always flow in such direction that it opposes the change or the cause the produced it.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |