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WorksheetsCET/NEET - Physics
Total questions: 60
Worksheet time: 30mins
Nature of equipotential surface for a point charge is
Ellipsoid with charge at foci
Sphere with charge at the centre of the sphere.
Sphere with charge on the surface of the sphere.
Plane with charge on the surface
A particle of mass 1gm and charge 1μC is held at rest on a frictionless horizontal surface at distance 1m from fixed charge 2mC. If the particle is released, it will be repelled. The speed of the particle when it is at a distance of 10m from the fixed charge.
60 ms-1
100 ms-1
90ms-1
180ms-1
Four metal plates are arranged as shown. Capacitance between X and Y (A = Area of each plate, d = distance between the plates).
Two point charges A = +3nC and B = +1nC are placed 5 Cm apart in air. The work done to move charge B towards A by 1 Cm is
1.35 X 10- 7J
2.7X 10- 7J
2X 10- 7J
12.1X 10- 7J
A system of two capacitors of capacitance 2μF and 4μF is connected in series across a potential difference of 6V. The electric charge and energy stored in the system are
10μC and 30μ J
36μC and 108μ J
8μC and 24μ J
1μC and 3μ J
The minimum value of effective capacitance that can be obtained by combining 3 capacitors of capacitances 1pF, 2pF and 4pF is
0.57pF
1pF
1.75pF
2pF
For the arrangement of capacitors as shown in the circuit, the effective capacitance between points A and B is
4μF
2μF
1μF
8μF
The work done to move a charge on any equipotential surface is
Infinity
Less than 1
Greater than 1
Zero
Two capacitors of 3μF and 6μF are connected in series and a potential difference of 900V is applied across the combination. They are then disconnected and reconnected in parallel. The potential difference across the combination is
Zero
100V
200V
400V
Two metal plates are separated by 2 Cm. The potentials of the plates are – 10 V and + 30V. The electric field between the two plates is
500V/m
1000V/m
2000V/m
3000V/m
A capacitor of capacitance C charged by an amount Q is connected in parallel with an uncharged capacitor of capacitance 2C. The final charges on the capacitors are
2Q ,2Q
4Q ,43Q
3Q, 32Q
5Q, 54Q
A system of two charges separated by a certain distance apart stores electrical potential energy. If the distance between them is increased, the potential energy of the system
Increases
Decreases
May increase or decrease
Remains same
The total energy of the electron orbiting around the nucleus in the ground state of the atom is
Less than zero
Zero
More than Zero
Sometimes less and sometime more than zero
Rutherford’s atomic model accounts for
Concentration of positive charge at the center in the atom
Stability of electron in orbits
Stability of the nucleus
Line spectrum of hydrogen
The scientist who is credited with the discovery of “Nucleus” in an atom
J.J. Thomson
Rutherford
Bohr
Balmer
In Bohr’s model of hydrogen atom, which of the following pairs of quantities are quantized?
Energy and linear momentum
Linear and angular momentum
Energy and angular momentum
None of the above
The orbital frequency of an electron in the hydrogen atom is proportional to
n3
n -3
n
n-1
Continuous emission spectrum is produced by
Incandescent electric lamp
Mercury vapor lamp
Sodium vapor lamp
None of the above
The nucleus of an atom consists of
Electrons and protons
Electrons, protons and neutrons
Electrons and neutrons
Neutrons and protons
Bohr’s atom model assumes
The nucleus is of infinite mass and is at rest
Electrons in a quantized orbit will not radiate energy
Mass of electron remains constant
All the above conditions
The angular momentum (L) of an electron moving in a stable orbit around nucleus is
Half integral multiple of 2πh
Integral multiple of h
Integral multiple of 2πh
Half integral multiple of h
Which state of triply ionized Beryllium (Be3+) has the same orbital radius as that of ground state of hydrogen
n = 3
n = 4
n = 1
n = 2
If the shortest wavelength in the Lyman series is 911.6 A0 the longest wavelength in the same series will be
1600A0
2430 A0
1215 A0
∞
For ionising an excited hydrogen atom, the energy required (in eV) will be
A little less than 13.6
13.6
More than 13.6
3.4 or less
Which one of the following pairs of nuclei are isotones?
34Se74, 31Ga71
38Sr84, 38Sr86
42Mo92, 40Zr92
20Ca40, 16S32
A nucleus represented by the symbol has
Z neutrons and A – Z protons
Z protons and A – Z neutrons
Z protons and A neutrons
A protons and Z – A neutrons
The mass number of a nucleus is
Always less than its atomic number
Always more than its atomic number
Sometimes equal to its atomic number
Sometimes less than and sometimes more than its atomic number
Atomic weight of Boron is 10.81 and it has two isotopes 5B10 and 5B11. Then the ratio of 5B10 : 5B11 in nature would be
15 : 16
10 : 11
19 : 81
81 : 19
The constituents of atomic nuclei are believed to be
Neutrons and protons
Protons only
Electrons and protons
Electrons, protons and neutrons
In the nucleus of 11Na23, the number of protons neutrons and electrons are
11, 12, 0
23, 12, 11
12, 11, 0
23, 11, 12
The nuclei 6C13 and 7N14 can be described as
isotones
isobars
isotopes of carbon
isotopes of nitrogen
If the nuclear radius of 27Al is 3.6 fermi, the approximate nuclear radius of 64Cu in fermi is
2.4
1.2
4.8
3.6
Two nuclei have their mass numbers in the ratio of 1 : 3. The ratio of their nuclear densities would be
(3)1/3 : 1
1 : 1
1 : 3
3 : 1
The volume occupied by an atom is greater than the volume of the nucleus by a factor of about
101
105
1010
1015
A nucleus break into two nuclear parts, which have their velocity ratio equal to 2 : 1. What will be the ratio of their nuclear size (nuclear radius)?
31/2 : 1
1 : 31/2
21/3 : 1
1 : 21/3
The mass number of He is 4 and that of sculpture is 32. The radius of sculpture nucleus is larger than that of helium by the factor of
4
2
8
3
To use a transistor as an amplifier
the emitter base junction is forward biased and the base collector junction is reversed biased
no bias voltage is required
both junction are forward biased
both junction are reverse biased
In semiconductors at a room temperature
the valence band is partially empty and the conduction band is partially filled
the valence band is completely filled and the conduction band is partially filled
the valence band is completely filled
the conduction band is completely empty
In a n-type semiconductor, which of the following statement is true?
Holes are minority carriers and pentavalent atoms are dopants
Holes are majority carriers and trivalent atoms are dopants
Electrons are majority carriers and trivalent atoms are dopants
Electrons are minority carriers and pentavalent atoms are dopants
If a small amount of antimony is added to germanium crystal
it becomes a p-type semiconductor
the antimony becomes an acceptor atom
there will be more free electrons than holes in the semiconductor
its resistance is increased
Which one of the following statement is false?
Pure Si doped with trivalent impurities gives ap-type semiconductor
Majority carriers in a n-type semiconductor are holes
Minority carriers in a p-type semiconductor are electrons.
The resistance of intrinsic semiconductor decreases with increase of temperature
In a p type semiconductor, the majority carriers of current are
Protons
electrons
holes
neutrons
Which of the following, when added as an impurity into the silicon produces n type semiconductor?
B
Al
P
Mg
To obtain a p-type germanium semiconductor, it must be doped with
indium
phosphorus
arsenic
antimony
When arsenic is added as an impurity to silicon, the resulting material is
n-type conductor
n-type semiconductor
p-type semiconductor
none of these
When n type semiconductor is heated
number of electrons increases while that of holes decreases
number of holes increases while that of electrons decreases
number of electrons and holes remain same
number of electrons and holes increases equally
Depletion layer consists of
mobile ions
protons
electrons
immobile ions
The depletion layer in the p-n junction region is caused by
drift of holes
diffusion of charge carriers
migration of impurity ions
drift of electrons
Which one of the following represents forward biasdiode?
Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is
0.75A
0A
0.25A
0.5 A
A wire of resistance 4 Ω is stretched to twice its original length. The resistance of stretched wire would be
8 Ω
16 Ω
2 Ω
4 Ω
What is the voltage drop across a 300Ω resistor carrying a current of 50mA.
15 V
20 V
25 V
30 V
The color code of a resistance is given Brown – Red – Orange – Gold. The values of resistance and tolerance, respectively, are
120Ω ± 5%
120Ω ± 10%
12KΩ ± 5%
12KΩ ± 10%
A carbon resistor of 1.5KΩ ±10% is to be marked with rings of different colours for its identification. The colour code sequence will be
Brown – Green – Orange – Silver
Brown – Green – Brown – Silver
Brown – Green– Red – Sliver
Brown – Green– Orange – Gold
A copper wire has a diameter of 0.5 mm and resistivity of 1.68 X 10-3 Ωm. What will be the length of this wire to make its resistance of 2Ω.
23.3m
20.3m
25.3m
30.3m
Specific resistance of a conductor increases with
Increase in temperature
Increase in cross-section area
Increase in cross-section and decrease in length
Decrease in cross-section area
The solids which have the negative temperature coefficient of resistance are
metals
insulators only
semiconductors only
insulators and semiconductors
Which of the following acts as a circuit protection device?
fuse
conductor
inductor
switch
Fuse wire is a wire of
High resistance and high melting point
High resistance and low melting point
Low resistance and low melting point
Low resistance and high melting point
In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60 W bulb for use in India is R, the resistance of a 60 W bulb for use in USA will be
R
2R
R/4
R/2
