An ellipsometer is an instrument for.
- AMeasuring stellar distance.
- BMeasuring the path of celestial bodies.
- CEnding curvature of elliptical surfaces.
- DStudying thin films on a solid surface.
An ellipsometer is an instrument for.
Explanation:
An ellipsometer is a device used for studying thin films on a solid surface.
Ellipsometry is an optical technique for investigating the di electric properties of thin films.
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Diameter of a plano–convex lens is 6 cm and thickness at the centre is 3 mm. If the speed of light in the material of the lens is 2 × 108 m/sec, the focal length of the lens is
|
(a) 15 cm |
(b) 20 cm |
(c) 30 cm |
(d) 10 cm |
A solenoid of 1.5 metre length and 4.0 cm diameter posses 10 turn per cm. A current of 5 ampere is flowing through it. The magnetic induction at axis inside the solenoid is
|
(a) 2π |
(b) 2π |
(c) 4π |
(d) 2π |
The neutron was discovered by
|
(a) Marie Curie |
(b) Pierre Curie |
(c) James Chadwick |
(d) Rutherford |
A person wears glasses of power – 2.5 D. The defect of the eye and the far point of the person without the glasses are respectively
|
(a) Farsightedness, 40 cm |
(b) Nearsightedness, 40 cm |
|
(c) Astigmatism, 40 cm |
(d) Nearsightedness, 250 cm |
A conducting loop carrying a current I is placed in a uniform magnetic field pointing into the plane of the paper as shown. The loop will have a tendency to
|
(a) Contract |
(b) Expand |
|
(c) Move towards +ve x –axis |
(d) Move towards –ve x-axis |
A circular loop of area carrying a current of 10 A, is held perpendicular to a magnetic field of intensity 0.1T. The torque acting on the loop is
|
(a) Zero |
(b) 0.01 N-m |
(c) 0.001 N-m |
(d) 0.8 N-m |
In a triode valve
|
(a) If the grid voltage is zero then plate current will be zero |
|
(b) If the temperature of filament is doubled, then the thermionic current will also be doubled |
|
(c) If the temperature of filament is doubled, then the thermionic current will nearly be four times |
|
(d) At a definite grid voltage the plate current varies with plate voltage according to Ohm’s law |
A particular emission line, detected in the light from a galaxy, has a wavelength , where
is the proper wavelength of the line. The galaxy distance from us
|
(a) 1.6 |
(b) 0.97 |
(c) 2.4 |
(d) 1.62 |
Vibration magnetometer works on the principle of
| (a) Torque acting on the bar magnet |
| (b) Force acting on the bar magnet |
| (c) Both the force and the torque acting on the bar magnet |
| (d) None of these |