Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is   and the fish is 12 cm below the surface, the radius of this circle in cm is

(a) 36

(b) 4

(c) 36

(d) 36/

When is hydrogen stable?

The electric resistance of a certain wire of iron is R. If its length and radius are both doubled, then:

Which of the following is true    

(a) Lyman series is a continuous spectrum

(b) Paschen series is a line spectrum in the infrared

(c) Balmer series is a line spectrum in the ultraviolet

(d) The spectral series formula can be derived from the Rutherford model of the hydrogen atom

The energy of a given sample of an ideal gas depends only on its:

1. Volume.
2. Pressure.
3. Density.
4. Temperature.

S is the surface of a lump of magnetic material:

Current density of a conductor is

Reciprocal of Impedance is:

A concave and convex lens have the same focal length of 20 cm and are put into contact to form a lens combination. The combination is used to view an object of 5 cm length kept at 20 cm from the lens combination. As compared to the object, the image will be

(a) Magnified and inverted

(b) Reduced and erect

(c) Of the same size as the object and erect

(d) Of the same size as the object but inverted

A sonometer wire supports a 4kg load and vibrates in fundamental mode with a tuning fork of frequency 416Hz. The length of the wire between the bridges is now doubled. In order to maintain fundamental mode, the load should be changed to:

1. 1kg
2. 2kg
3. 8kg
4. 16kg.