Physics Test

Question 1
1 / -0

What is the force between two small charged spheres having charges of \(2 \times 10^{-7} \mathrm{C}\) and \(3 \times 10^{-7} \mathrm{C}\) placed \(30 \mathrm{~cm}\).

A
\(6 \times 10^{-3} \mathrm{~N}\)

B
\(6.994 \times 10^{-3} \mathrm{~N}\)

C
\(5.994\times 10^{-3} \mathrm{~N}\)

D
\(7.994\times 10^{-3} \mathrm{~N}\)

Question 2
1 / -0

A step down transformer connected to an ac mainssupply of 220 V is made to operate at 11 V, 44 Wlamp. Ignoring power losses in the transformer,what is the current in the primary circuit?

A
4 A

B
0.2 A

C
0.4 A

D
2 A

Question 3
1 / -0

When the energy of the incident radiation is increased by \(20 \%\). The kinetic energy of the photoelectrons emitted from a metal surface increased from \(0.5 \mathrm{eV}\) to \(0.8 \mathrm{eV}\). The work function of the metal is:

A
\(0.65 \mathrm{eV}\)

B
\(1.0 \mathrm{eV}\)

C
\(1.3 \mathrm{eV}\)

D
\(1.5 \mathrm{eV}\)

Question 4
1 / -0

An iron ball is having radius \(0.04\) m. A charge of \(1.6 \times 10^{-7}\) C is uniformly distributed over its surface. What is the electric field at a point \(0.2\) m from the centre of it?

A
\(3.6 \times 10^{4}~NC ^{-1}\)

B
\(4.46 \times 10^{4}~NC ^{-1}\)

C
\(5 \times 10^{4}~NC ^{-1}\)

D
\(0.38 \times 10^{4}~NC ^{-1}\)

Question 5
1 / -0

A parallel plate capacitor is made of two square plates of side ' \(a\) ', separated by a distance \(\mathrm{d}\) \((\mathrm{d}<<\) a). The lower triangular portion is filled with a dielectric of dielectric constant \(\mathrm{K}\), as shown in the figure. Capacitance of this capacitor is:

A
\(\frac{\mathrm{K} \in_0 \mathrm{a}^2}{2 \mathrm{~d}(\mathrm{~K}+1)}\)

B
\(\frac{\mathrm{K} \in_0 \mathrm{a}^2}{\mathrm{~d}(\mathrm{~K}-1)} ln k\)

C
\(\frac{\mathrm{K} \in_0 \mathrm{a}^2}{\mathrm{~d}} lnk\)

D
\(\frac{1}{2} \frac{\mathrm{K} \in_0 \mathrm{a}^2}{\mathrm{~d}}\)

Question 6
1 / -0

The intensity of the magnetic induction field at the centre of a single turn circular coil of radius 5 cm carrying current of 0.9 A is:

A
36π × 10^-7 T

B
9π × 10^-7 T

C
36π × 10^-6T

D
9π × 10^-6 T

Question 7
1 / -0

The magnetic flux \(\phi\) (in weber) linked with a coil of resistance \(10 \Omega\) varies with time \(t\) (in second) as \(\phi=8 t^{2}-4 t+1\). The current induced in the coil at \(t=0.1 \mathrm{sec}\) is:

A
\(10 \mathrm{~A}\)

B
\(0.24 \mathrm{~A}\)

C
\(0.12 \mathrm{~A}\)

D
\(4.8 \mathrm{~A}\)

Question 8
1 / -0

In a pond of water, a flame is held \(2 \mathrm{~m}\) above the surface of water. A fish is at depth of \(4 \mathrm{~m}\) from water surface. Refractive index of water is \(\frac{4}{3}\). The apparent height of the flame from the eyes of fish is:

A
\(5.5 \mathrm{~m}\)

B
\(6 \mathrm{~m}\)

C
\(\frac{8}{3} \mathrm{~m}\)

D
\(\frac{20}{3} \mathrm{~m}\)

Question 9
1 / -0

Light from a point source in the air falls on a spherical glass surface (μ=1.5 and radius of curvature 20 cm). The distance of the light source from the glass surface is 100 cm. The position where the image is formed is:

A
\(50 \mathrm{~cm}\)

B
\(100 \mathrm{~cm}\)

C
\(125 \mathrm{~cm}\)

D
\(25 \mathrm{~cm}\)

Question 10
1 / -0

What is the expression for the Current Amplification factor?

A
\(\frac{\Delta I_{c}}{\Delta V_{c}}\)

B
\(\frac{\Delta V_{c}}{\Delta I_{c}}\)

C
\(\left(\frac{\Delta I_{E}}{\Delta I_{B}}\right)_{V_{C E}}\)

D
\(\left(\frac{\Delta I_{C}}{\Delta I_{B}}\right)_{V_{B E}}\)

Question 11
1 / -0

Why is salt added in ice creams?

A
Salt decreases melting point of the ice cream

B
Salt increases the melting point of ice cream

C
Salt enhances the taste of ice cream

D
None of these

Question 12
1 / -0

A fixed non conducting smooth track is in the shape of a quarter circle of radius \(\mathrm R\) in vertical plane. A small metal ball \(\mathrm A\) is fixed at the bottom of the track. Another identical ball \(\mathrm B\), which is free to move, is placed in contact with ball A. A charge \(\mathrm Q\) is given to ball \(\mathrm A\) which gets equally shared by the two balls. Ball \(\mathrm B\) gets repelled and ultimately comes to rest in its equilibrium position where its radius vector makes an angle \(\theta\left(\theta<90^{\circ}\right)\) with vertical. Mass of ball is \(\mathrm m\). Find charge \(\mathrm Q\) that was given to the balls.

A
\(9 \mathrm R \sin \left(\frac{\theta}{2}\right) \sqrt{2 \pi \varepsilon_0 m g \sin \left(\frac{\theta}{2}\right)}\)

B
\(8 \mathrm R \sin \left(\frac{\theta}{2}\right) \sqrt{2 \pi \varepsilon_0 m g \sin \left(\frac{\theta}{2}\right)}\)

C
\(6 \mathrm R \sin \left(\frac{\theta}{2}\right) \sqrt{2 \pi \varepsilon_0 m g \sin \left(\frac{\theta}{2}\right)}\)

D
\(4 \mathrm R \sin \left(\frac{\theta}{2}\right) \sqrt{2 \pi \varepsilon_0 m g \sin \left(\frac{\theta}{2}\right)}\)

Question 13
1 / -0

If one of the two electrons of a \(\mathrm{H}_{2}\) molecule is removed, we get a hydrogen molecular ion \(\mathrm{H}_{2}^{+}\). In the ground state of a \(\mathrm{H}_{2}^{+}\), the two protons are separated by roughly \(1.5 \mathring{A},\) and the electron is roughly \(1 \mathring{A}\) from each proton. Determine the potential energy of the system.

A
\(-17.2 \mathrm{e} \mathrm{V}\)

B
\(-19.2 \mathrm{e} \mathrm{V}\)

C
\(-18.2 \mathrm{e} \mathrm{V}\)

D
\(-12.2 \mathrm{e} \mathrm{V}\)

Question 14
1 / -0

A series LCR circuit containing \(5.0 \mathrm{H}\) inductor, 80 \(\mu \mathrm{F}\) capacitor and \(40 \Omega\) resistor is connected to 230 \(\mathrm{V}\) variable frequency ac source. The angular frequencies of the source at which power transferred to the circuit is half the power at the resonant angular frequency are likely to be:

A

42 rad/s, and 58 rad/s

B

25 rad/s, and 75 rad/s

C

50 rad/s, and 25 rad/s

D

46 rad/s, and 54 rad/s

Question 15
1 / -0

When photons of energy hv fall on an aluminium plate (of work function E₀), photoelectrons of maximum kinetic energy K are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be:

A
\(K+E_{0}\)

B
\(2 K\)

C
\(K\)

D
\(K+h v\)

Submit Test

Physics Test - ...

Question 1

\(6 \times 10^{-3} \mathrm{~N}\)

\(6.994 \times 10^{-3} \mathrm{~N}\)

\(5.994\times 10^{-3} \mathrm{~N}\)

\(7.994\times 10^{-3} \mathrm{~N}\)

Question 2

4 A

0.2 A

0.4 A

2 A

Question 3

\(0.65 \mathrm{eV}\)

\(1.0 \mathrm{eV}\)

\(1.3 \mathrm{eV}\)

\(1.5 \mathrm{eV}\)

Question 4

\(3.6 \times 10^{4}~NC ^{-1}\)

\(4.46 \times 10^{4}~NC ^{-1}\)

\(5 \times 10^{4}~NC ^{-1}\)

\(0.38 \times 10^{4}~NC ^{-1}\)

Question 5

\(\frac{\mathrm{K} \in_0 \mathrm{a}^2}{2 \mathrm{~d}(\mathrm{~K}+1)}\)

\(\frac{\mathrm{K} \in_0 \mathrm{a}^2}{\mathrm{~d}(\mathrm{~K}-1)} ln k\)

\(\frac{\mathrm{K} \in_0 \mathrm{a}^2}{\mathrm{~d}} lnk\)

\(\frac{1}{2} \frac{\mathrm{K} \in_0 \mathrm{a}^2}{\mathrm{~d}}\)

Question 6

36π × 10-7 T

9π × 10-7 T

36π × 10-6 T

9π × 10-6 T

Question 7

\(10 \mathrm{~A}\)

\(0.24 \mathrm{~A}\)

\(0.12 \mathrm{~A}\)

\(4.8 \mathrm{~A}\)

Question 8

\(5.5 \mathrm{~m}\)

\(6 \mathrm{~m}\)

\(\frac{8}{3} \mathrm{~m}\)

\(\frac{20}{3} \mathrm{~m}\)

Question 9

\(50 \mathrm{~cm}\)

\(100 \mathrm{~cm}\)

\(125 \mathrm{~cm}\)

\(25 \mathrm{~cm}\)

Question 10

\(\frac{\Delta I_{c}}{\Delta V_{c}}\)

\(\frac{\Delta V_{c}}{\Delta I_{c}}\)

\(\left(\frac{\Delta I_{E}}{\Delta I_{B}}\right)_{V_{C E}}\)

\(\left(\frac{\Delta I_{C}}{\Delta I_{B}}\right)_{V_{B E}}\)

Question 11

Salt decreases melting point of the ice cream

Salt increases the melting point of ice cream

Salt enhances the taste of ice cream

None of these

Question 12

\(9 \mathrm R \sin \left(\frac{\theta}{2}\right) \sqrt{2 \pi \varepsilon_0 m g \sin \left(\frac{\theta}{2}\right)}\)

\(8 \mathrm R \sin \left(\frac{\theta}{2}\right) \sqrt{2 \pi \varepsilon_0 m g \sin \left(\frac{\theta}{2}\right)}\)

\(6 \mathrm R \sin \left(\frac{\theta}{2}\right) \sqrt{2 \pi \varepsilon_0 m g \sin \left(\frac{\theta}{2}\right)}\)

\(4 \mathrm R \sin \left(\frac{\theta}{2}\right) \sqrt{2 \pi \varepsilon_0 m g \sin \left(\frac{\theta}{2}\right)}\)

Question 13

\(-17.2 \mathrm{e} \mathrm{V}\)

\(-19.2 \mathrm{e} \mathrm{V}\)

\(-18.2 \mathrm{e} \mathrm{V}\)

\(-12.2 \mathrm{e} \mathrm{V}\)

Question 14

42 rad/s, and 58 rad/s

25 rad/s, and 75 rad/s

50 rad/s, and 25 rad/s

46 rad/s, and 54 rad/s

Question 15

\(K+E_{0}\)

\(2 K\)

\(K\)

\(K+h v\)

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Question Analysis

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36π × 10^-7 T

9π × 10^-7 T

36π × 10^-6T

9π × 10^-6 T