Alternating Current — Physics STD 12 Science — Question

The relation between the wavelength and linear momentum for a particle in motion was given by :

Which one of the following is a non-magnetic substance

(a) Iron

(b) Nickel

(c) Cobalt

(d) Brass

When a beam of accelerated electrons hits a target, a continuous X-ray spectrum is emitted from the target. Which of the following wavelength is absent in the X-ray spectrum, if the X-ray tube is operating at 40,000 volts

(a) 0.25 Å

(b) 0.5 Å

(c) 1.5 Å

(d) 1.0 Å

The only property possessed by ferromagnetic substance is

(a) Hysteresis	(b) Susceptibility
(c) Directional property	(d) Attracting magnetic substances

In a plano-convex lens the radius of curvature of the convex lens is 10 cm.  If the plane side is polished, then the focal length will be (Refractive index = 1.5)

(a) 10.5 cm

(b) 10 cm

(c) 5.5 cm

(d) 5 cm

The strength of the earth’s magnetic field is:

The ratio between Bohr radii is:

If 4   energy is required to move a charge of 0.25 coulomb between two points. Then what will be the potential difference between them

(a) 178 V

(b) 256 V

(c) 356 V

(d) None of these

The shortest wavelength in the Lyman series of hydrogen spectrum is 912 Å corresponding to a photon energy of 13.6 eV. The shortest wavelength in the Balmer series is about

(a) 3648 Å

(b) 8208 Å

(c) 1228 Å

(d) 6566 Å

The temperature of an object is observed to rise in a period. In this period:

1. Heat is certainly supplied to it.
2. Heat is certainly not supplied to it.
3. Heat may have been supplied to it.
4. Work may have been done on it.