The minimum energy to ionize an atom is the energy required to
add one electron to the atom
excite the atom from its ground state to its excited state
remove one outer most electron from the atom
remove one inner most electron from the atom
The distance between two point objects P and Q is 32 cm. A convex lens of focal length 15 cm is placed between them, so that the images of both the objects are formed at the same place. The distance of P from the lens could be
20 cm
12 cm
18 cm
28 cm
To get an output Y =1 from circuit of figure, the input must be
A = 0, B = 1, C = 0
A = 0, B = 0, C = 1
A = 1, B = 0, C = 0
A = 1, B = 0, C = 1
In hydrogen atom, the electron in a given orbit has total energy -1.5 eV. The potential energy is
1.5 eV
- 1.5 eV
3.0 eV
- 3.0 eV
The radii of curvature of the two surfaces of a lens are 20 cm and 30 cm and the repeative index of the material of the lens is 1.5. If the lens is concave-convex, then the focal length of the lens is
24 cm
10 cm
15 cm
120 cm
In a transistor circuit, the base current changes from 30 µA to 90 µA. If the current gain of the transistor is 30%, the change in the collector current is
4 mA
2 mA
3.5 mA
1.8 mA
In a full wave rectifier, input AC current has a frequency v. The output frequency of current is
v
2 v
None of these
When the distance between slits of Young's double slit experiment is reduced to half then the fringe middle will become
constant
four times
two times
half
C.
two times
Light of wavelength 488 nm is produced by organ laser, which is used in the photoelectric effect. When light from this spectral line is incident on the emitter, the stopping (cut-off) potential of photoelectron is 0.38 V. Find the work function of the material from which the emitter is made.
1.25 eV
2.17 eV
4.07 eV
3.57 eV
A beam of light after reflection on a plane mirror forms a real image. The beam is
convergent
divergent
parallel to axis
parallel but not to axis of mirror