12th Standard Syllabus & Materials
12th Standard
TN 12th Computer Applications மின்னணு தரவு பரிமாற்றம் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications மின் - வணிக பாதுகாப்பு அமைப்புகள் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications மின்னணு செலுத்தல் முறைகள் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications மின் - வணிகம் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications திறந்த மூல கருத்துருக்கள் Sample Question Papers Study Material - QB365 Set A
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TN 12th Computer Applications வலையமைப்பு வடமிடல் Sample Question Papers Study Material - QB365 Set A
Published on: 12/10/2020
12th Standard Physics English Medium Free Online Test 1 mark questions 2020 Part Two
Download Tamil Nadu 12th Standard Physics question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
Questions + Answers key
Take MCQ Physics Test1.
The minimum potential given to the anode for which the photoelectric current becomes zero is called _______ potential.
cut-off
threshold
saturation
active
2.
Sodium and copper have work functions of 2.3eV and 4.5eV respectively, then the ratio of the wavelengths is nearest to ___________.
1: 2
4: 1
2: 1
1: 4
3.
4.
Which one of the following represents forward bias diode?
5.
6.
Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is _____.
\(\frac { hc }{ \lambda } -{ m }_{ e }+\frac { e^{ 2 }{ B }^{ 2 }{ R }^{ 2 } }{ { 2m }_{ e } } \)
\(\frac { hc }{ \lambda } +{ 2m }_{ e }{ \left[ \frac { eBR }{ { 2m }_{ e } } \right] }^{ 2 }\)
\(\\ \frac { hc }{ \lambda } -{ m }_{ e }{ c }^{ 2 }-\frac { e^{ 2 }{ B }^{ 2 }{ R }^{ 2 } }{ { 2m }_{ e } } \)
\(\frac { hc }{ \lambda } -{ 2m }_{ e }{ \left[ \frac { eBR }{ { 2m }_{ e } } \right] }^{ 2 }\)
7.
If the velocity and wavelength of light in air is Va and λa and that in water is Vw and λw, then the refractive index of water is______.
\(\frac{V_W}{V_a}\)
\(\frac{V_a}{V_W}\)
\(\frac{\lambda_W}{\lambda_a}\)
\(\frac{{V_a}\lambda_a}{{V_W}\lambda_W}\)
8.
Which one of the following groups of electromagnetic waves is in order of increasing frequency?
Microwaves U-V rays, X-rays
Radio waves, visible light and 1-R rays
gamma rays U-V rays radio waves
gamma rays, U-V rays radio waves
9.
Which EM waves are used in medicine to destroy cancer cells?
radio waves
IR
૪ rays
UV rays
10.
The phase difference between VL and Vc is _________________
2π
π/2
π/4
π
11.
An electron of mass 0.90 x 10-30kg under the action of a magnetic field moves in a circle of 2cm radius at a speed of 3 x 106 m/s if a proton of mass 1.8 x 10-27 kg was to move in a circle of the same radius in the same magnetic field, then its speed will be _______________.
3.0 x 106 m/s
1.5 x 103 m/s
6.0 x 104 m/s
cannot be estimated from the same data
12.
In Fleming's right hand rule, the forefinger represents the direction of ____________.
motion of the conductor
magnetic field
induced current
induced emf
13.
By using law of conservation of electric charge balance the following equations:
92U238 ⇾ 90Th234 +________.
2He4
1H3
1H2
1H1
14.
The curve representing Ohm's law is a ________________.
linear
parabola
hyperbola
none of the above
15.
The value of current I in the network as shown is
\(\cfrac { 1 }{ 9 } A\)
\(\cfrac { 2 }{ 9 } A\)
\(\cfrac { 3 }{ 9 } A\)
1A
16.
The current in the given circuit is __________________.
\(\cfrac { 1 }{ 8 } A\)
\(\cfrac { 2 }{ 9 } A\)
\(\cfrac { 2 }{ 9 } A\)
\(1A\)
17.
When 'n' resistors of equal resistance (R) are connected in series and in parallel respectively, then the ratio of their effective resistance is ______________
1: n2
n2: 1
n: 1
1: n
18.
A charge q1 exerts force on charge q2. If another charge q3 is brought near, the force of q1, exerted on q2, will be
decreased
increased
remains unchanged
increased if q3 is of same sign as q1 and decreased if q2 is of opposite sign.
19.
In a parallel plate capacitor of capacitance C, a metal sheet is inserted between the plates, parallel to them. The thickness of the sheet is half of the separation between the plates. The capacitance now becomes
2C
\(\frac{C}{4}\)
4C
\(\frac{C}{2}\)
20.
What will happen if two conducting spheres are separately charged and then brought in contact?
Total charge on the two spheres is conserved
The total energy is conserved
Both charge and energy are conserved
The final potential is the mean of the original potentials.
21.
A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively. The magnetic induction at the centre of the spiral is ______.
\(5\mu T\)
\(7\mu T\)
\(8\mu T\)
\(10\mu T\)
22.
The flux linked with a coil at any instant t is given by \(\Phi\)B = 10t2 − 50t + 250. The induced emf at t = 3s is
−190 V
−10 V
10 V
190 V
23.
The electric and the magnetic fields, associated with an electromagnetic wave, propagating along negative X axis can be represented by _____.
\(\vec { E } ={ E }_{ 0 }\hat { i } \) and \(\vec { B } ={ B }_{ 0 }\hat { k } \)
\(\vec { E } ={ E }_{ 0 }\hat { k } \) and \(\vec { B } ={ B }_{ 0 }\hat { j } \)
\(\vec { E } ={ E }_{ 0 }\hat { i } \) and \(\vec { B } ={ B }_{ 0 }\hat { j } \)
\(\vec { E } ={ E }_{ 0 }\hat { j } \) and \(\vec { B } ={ B }_{ 0 }\hat { i } \)
24.
Which charge configuration produces a uniform electric field?
point charge
uniformly charged infinite line
uniformly charged infinite plane
uniformly charged spherical shell
25.
What is the value of resistance of the following resistor?
100 k Ω
10 k Ω
1 k Ω
1000 k Ω
1.
(a)
cut-off
2.
(c)
2: 1
3.
(c)
4.
(a)
5.
(b)
6.
\(\text {K.E } =\frac{B^2 q^2 r^2}{2 m} \)
\(\phi =\frac{h c}{\lambda}-K . E \)
\(=\frac{h c}{\lambda}-\frac{B^2 q^2 r^2}{2 m} \)
\(\phi =\frac{h c}{\lambda}-2 m\left(\frac{B q r}{2 m}\right)^2\)
7.
Refractive index of water \(=\frac{Velocity \ of \ light \ in \ air(V_s)}{Velocity \ of \ light \ in \ water(V_w)}\)
8.
(a)
Microwaves U-V rays, X-rays
9.
(c)
૪ rays
10.
(d)
π
11.
(b)
1.5 x 103 m/s
12.
(b)
magnetic field
13.
(a)
2He4
14.
(c)
hyperbola
15.
(d)
1A
16.
(d)
\(1A\)
17.
(b)
n2: 1
18.
(c)
remains unchanged
19.
(a)
2C
20.
(a)
Total charge on the two spheres is conserved
21.
(b)
\(7\mu T\)
22.
\(\phi_B =10 t^2-50 t+250 \)
\(e =\frac{-d \phi_B}{d t} \)
\(=\frac{-d}{d t}\left(10 t^2-50 t+250\right) \)
=-(20 t - 50)
=-20 t + 50
When, t = 3 s, e =-20(3) + 50 = -60 + 50
e = -10V
23.
\( { E } ={ E }_{ 0 }\hat { k } \) and \({ B } ={ B }_{ 0 }\hat { j } \)
24.
(c)
uniformly charged infinite plane
25.
Brown - 1
Black - 0
Yellow - 104
(∴ R = 10 x 104 Ω = 100 kΩ)
12th Standard Syllabus & Materials
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