Test
Physics
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Preguntas del test (21)
1In the Bohr model of the hydrogen atom, let R, V and E represent the radius of the orbit, the speed of electron and the total energy of the electron respectively. Which of the following quantity is proportional to the quantum number n?
- AVR
- BRE
- CE/V
- DR/E
2The work function for aluminium is 4.125 eV. The cut off wavelength for photoelectric effect for Aluminium is
- A200 nm
- B300 nm
- C150 nm
- D420 nm
3The electron is a hydrogen atom makes a transition from n = n1 to n = n2 state. The time period of the electron in the final state is eight times that in the initia state. Then the possible values of n1 and n2 are
- An1 = 8, n2 = 2
- Bn1 = 4, n2 = 2
- Cn1 = 6, n2 = 2
- Dn1 = 1, n2 = 2
4Light of frequency 1.5 times the threshold frequency is incident on photosensitive material. If the frequency is halved and intensity is doubled, the photocurrent becomes
- AQuadrupled
- BDoubled
- CZero
- DHalved
5 A radioactive substance has a half life of four months. Three fourth of the substance will decay in
- A12 months
- B4 months
- C8 months
- D3 months
6A radio isotope has a half life of 5 years. The fraction of the atoms of this material that would decay in 15 years will be
- A1
- B2/3
- C7/8
- D5/8
7When Boron 5B10 is bombarded by neutron, particles are emitted. The resulting nucleus has mass number
- A11
- B6
- C7
- D15
8Tracer techniques make use of
- Aneutron scattering
- Belectron beams
- Clasers
- Dradioactive isotopes
9A sample of radioactive substance contains 2,828 atoms. If its half life is two days, how many atoms will be left intact in the sample after one day?
- A2,000
- B1,000
- C1,414
- D707
10The unit of Planck’s constant is
- ANm
- BeV
- CJs–1
- DJs
11 Mean life of a radioactive element is one year. Then its half life is (years)
- A0.5
- B0.4
- C1
- D0.693
12 Hydrogen atom emits blue light when it jumps from n = 4 energy level to the n = 2 energy level. Which colour of light would the atom emit when it jumps from the n = 5 level to the n = 2 level?
- ARed
- BYellow
- CGreen
- DViolet
13The electromagnetic theory of light was developed by
- AMax Planck
- BMaxwall
- CNewton
- DHuygens
14The concept of quantum nature of light has emerged in an attempt to explain
- Ablack – body radiation
- Bphotoelectric effect
- Cpolarisation of light
- Dinterference and diffraction.
15The electron in the innermost orbit of an atom has _____ velocity.
- Amean
- Bzero
- Chighest
- Dlowest
16 Einstein’s photoelectric equation was experimentally verified by
- AMillikan
- BRutherford
- CEinstein
- DFermi
- Eall the above
17A photon of energy 8 eV is incident on a metal surface of threshold frequency 1.6 1015 Hz. The K.E of the photoelectrons emitted (in eV) (Take h = 6 10–34 Js)
- A2
- B1.2
- C1.6
- D6
18 TV waves have a wavelength range of 1-10 metre. This frequency range in MHz is
- A3 – 3000
- B300 – 3000
- C3 – 30
- D30 – 300
19. An electron and a proton have the same de-Broglie wavelength. Then the kinetic energy of the electron is
- Agreater than the kinetic energy of the proton
- Bzero
- CInfinity
- Dequal to the kinetic energy of the proton
20Whenever a hydrogen atom emits a photon in the Balmer series
- AIt may emit another photon in the Balmer series
- BIt must emit another photon in the Lyman series
- CIt may emit another photon in the Paschen series
- DIt need not emit any more photon
21The de Broglie wavelength of an electron in the first Bohr orbit is
- Aequal to the circumference of the first orbit
- Bequal to twice the circumference of the first orbit
- Cequal to half the circumference of the first orbit
- Dequal to one fourth the circumference of the first orbit
Información
- Descripción
- Test sobre Physics, creado por raghu Katagall el 09/11/2017.
- Autor
- raghu Katagall
- Idioma
- English
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- 2.168
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- Valoración
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