MCQOPTIONS
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MCQOPTIONS
This section includes 9 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Let a total charge 2Q be distributed in a sphere of radius R, with the charge density given by ρ(r) = kr, where r is the distance from the centre. Two charges A and B, of -Q each, are placed on diametrically opposite points, at equal distance, ‘a’ from the centre. If A and B do not experience any force, then: |
| A. | a = 8-1/4R |
| B. | \({\rm{a}} = \frac{{3{\rm{R}}}}{{{2^{1/4}}}}\) |
| C. | a = 2-1/4R |
| D. | \({\rm{a}} = \frac{{\rm{R}}}{{\sqrt 3 }}\) |
| Answer» B. \({\rm{a}} = \frac{{3{\rm{R}}}}{{{2^{1/4}}}}\) | |
| 2. |
In the above circuit, \(C = \sqrt {\frac{3}{2}} \;\mu F,{R_2} = 20\Omega ,\;L = \frac{{\sqrt 3 }}{{10}}H\) and R1 = 10 Ω Current in L – R1 path is I1 and in C - R2 path is I2. The voltage of AC source is given by \(V = 200\sqrt 2 \;sin\left( {100t} \right)\) difference between I1 and I2 is |
| A. | 30° |
| B. | 60° |
| C. | 150° |
| D. | 90° |
| Answer» D. 90° | |
| 3. |
A positive charge +q is placed at the centre of a hollow metallic sphere of inner radius a and outer radius b. the electric field at a distance r from the centre is denoted by E. In this regards, which one of the following statement is correct? |
| A. | E = 0 for a < r < b |
| B. | E = 0 for r < a |
| C. | E = q / 4πϵ0r for a < r < b> |
| D. | E = q / 4πϵ0r for r < a |
| Answer» B. E = 0 for r < a | |
| 4. |
If a free electron moves through a potential difference of 1 kV, then the energy gained by the electron is given by |
| A. | 1.6 × 10-19 J |
| B. | 1.6 × 10-16 J |
| C. | 1 × 10-19 J |
| D. | 1 × 10-16 J |
| Answer» C. 1 × 10-19 J | |
| 5. |
A parallel plate capacitor with plates of area 1 m2 each, are at a separation of 0.1 m. If the electric field between the plates is 100 N/C, the magnitude of charge on each plate is \(\left( {{\rm{Take,\;}}{{\rm{\varepsilon }}_0} = 8.85 \times {{10}^{ - 12}}\frac{{{{\rm{C}}^2}}}{{{\rm{N}} - {{\rm{m}}^2}}}} \right)\) |
| A. | 9.85 × 10-10 C |
| B. | 8.85 × 10-10 C |
| C. | 7.85 × 10-10 C |
| D. | 6.85 × 10-10 C |
| Answer» C. 7.85 × 10-10 C | |
| 6. |
A parallel plate capacitor with air between the plates, has a capacitance of 2 pF. The plate separation is doubled and a dielectric slab is inserted so that it completely fills the space between the plates. The capacitance of the capacitor becomes 4 pF. The dielectric constant of the slab is: |
| A. | 0.5 |
| B. | 2 |
| C. | 4 |
| D. | 8 |
| Answer» D. 8 | |
| 7. |
Four point charges -q, +q, +q and -q are placed on y-axis at y = -2d, y = -d, y = +d and y = +2d, respectively. The magnitude of the electric field E at a point on the x-axis at x = D, with D >> d, will behave as: |
| A. | \(E \propto \frac{1}{{{D^3}}}\) |
| B. | \(E \propto \frac{1}{D}\) |
| C. | \(E \propto \frac{1}{{{D^4}}}\) |
| D. | \(E \propto \frac{1}{{{D^2}}}\) |
| Answer» D. \(E \propto \frac{1}{{{D^2}}}\) | |
| 8. |
Determine the electric dipole moment of the system of three charges, placed on the vertices of an equilateral triangle as shown in the figure. |
| A. | \(\sqrt 3 ql\frac{{\hat j - \hat i}}{{\sqrt 2 }}\) |
| B. | \(2ql\hat j\) |
| C. | \(- \sqrt 3 ql\hat j\) |
| D. | \(\left( {ql} \right)\frac{{\hat i + \hat j}}{{\sqrt 2 }}\) |
| Answer» D. \(\left( {ql} \right)\frac{{\hat i + \hat j}}{{\sqrt 2 }}\) | |
| 9. |
A parallel plate capacitor is made of two square plates of side 'a', separated by a distance d (d |
| A. | \(\frac{{{\rm{K}}{\epsilon _0}{{\rm{a}}^2}}}{{2{\rm{d}}\left( {{\rm{K}} + 1} \right)}}\) |
| B. | \(\frac{{{\rm{K}}{\epsilon _0}{{\rm{a}}^2}}}{{{\rm{d}}\left( {{\rm{K}} - 1} \right)}}{\rm{ln\;K}}\) |
| C. | \(\frac{{{\rm{K\epsilon_0}}{{\rm{a}}^2}}}{{\rm{d}}}{\rm{ln\;K}}\) |
| D. | \(\frac{1}{2}\frac{{{\rm{K\epsilon_0}}{{\rm{a}}^2}}}{{\rm{d}}}\) |
| Answer» C. \(\frac{{{\rm{K\epsilon_0}}{{\rm{a}}^2}}}{{\rm{d}}}{\rm{ln\;K}}\) | |