The resistances of three parts of a circular loop are as shown in the figure. What will be the magnetic field at the centre of \(O\) 
(current enters at \(A\) and leaves at \(B\) and \(C\) as shown)?

1. \(\dfrac{\mu_{0} I}{6 a}\) 2. \(\dfrac{\mu_{0} I}{3 a}\)
3. \(\dfrac{2\mu_{0} I}{3 a}\) 4. \(0\)

Subtopic:  Magnetic Field due to various cases |
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The galvanometer of resistance \(80~\Omega\) deflects a full scale for a potential of \(20\) mV. How much resistance is required for a voltmeter to deflect a full scale of \(5\) V to be made using this galvanometer?
1.  resistance of \(19.92~ \text{k} \Omega\) parallel to the galvanometer
2. resistance of \(19.92~ \text{k} \Omega\) in series with the galvanometer
3. resistance of \(20 ~\Omega\) parallel to the galvanometer
4. resistance of \(20~ \Omega\) in series with the galvanometer
Subtopic:  Conversion to Ammeter & Voltmeter |
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Consider six wires with the same current flowing through them as they enter or exit the page. Rank the magnetic field's line integral counterclockwise around each loop, going from most positive to most negative.

   
1. \(B>C>D>A\)
2. \(B>C=D>A\)
3. \(B>A>C=D\)
4. \(C>B=D>A\)

Subtopic:  Ampere Circuital Law |
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Suppose a cyclotron is operated at an oscillator frequency of 12 MHz and a discharge radius of 53 cm. What is the resulting kinetic energy of the deuterons?
(Mass of deuteron, \(m=3.34\times10^{-27}\) kg)

1. 16.6 MeV
2. 12 MeV
3. 15 MeV
4. 14 MeV

Subtopic:  Cyclotron (OLD NCERT) |
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A neutron, a proton, an electron and an \(\alpha\text-\)particle enter a region of the uniform magnetic field with the same velocity. The magnetic field is perpendicular and directed into the plane of the paper. The tracks of the particles are labelled in the figure. Which track will the \(\alpha\text-\)particle follow?
             

1. \(A\) 2. \(B\)
3. \(C\) 4. \(D\)
Subtopic:  Lorentz Force |
 60%
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Which of the following statements about cyclotron is correct?

1. A charged particle accelerates only between the dees because of the magnetic field.
2. A charged particle accelerates only between the dees because of the electric field.
3. A charged particle slows down within the dees and speeds up between the dees.
4. A charged particle continuously accelerates all the time.
Subtopic:  Cyclotron (OLD NCERT) |
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A charged particle is projected through a region in a gravity-free space. If it passes through the region with constant speed, then the region may have:
1. \(\vec{E}=0, \vec{B} \neq 0\)
2. \(\vec{E} \neq 0, \vec{B} \neq 0\)
3. \(\vec{E} \neq 0, \vec{B}=0\)
4. Both (1) & (2)

Subtopic:  Lorentz Force |
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What is the primary function of the electric field in a cyclotron?

1. energize the charged particle.

2. bring the charged particle again and again into the field.

3. cancel the force due to the magnetic field.

4. guide charged particles to the exit part.

Subtopic:  Cyclotron (OLD NCERT) |
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Which one of the following expressions represents Biot-Savart's law? Symbols have their usual meanings.

1. \(\overrightarrow{d B}=\frac{\mu_0 \mathrm{I}(\overrightarrow{d l} \times \hat r)}{4 \pi|\overrightarrow{\mathrm{r}}|^3}\\ \) 2. \(\overrightarrow{d B}=\frac{\mu_0 \mathrm{I}(\overrightarrow{d l} \times \hat r)}{4 \pi|\overrightarrow{\mathrm{r}}|^2} \)
3. \(\overrightarrow{d B}=\frac{\mu_0 \mathrm{I}(\overrightarrow{d l} \times \vec{r})}{4 \pi|\vec{r}|^3} \) 4. \(\overrightarrow{d B}=\frac{\mu_0 \mathrm{I}(\overrightarrow{d l} \cdot \vec{r})}{4 \pi|\overrightarrow{\mathrm{r}}|^3}\)
Subtopic:  Biot-Savart Law |
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On connecting a shunt of \(10 ~ \Omega,\) the deflection in a moving coil galvanometer falls from \(40\) divisions to \(6\) divisions. What is the resistance of the galvanometer?
1.  \(\frac{120}{3}~\Omega \) 2. \(\frac{30}{7}~\Omega \)
3. \(\frac{170}{3}~\Omega \) 4. \(\frac{150}{7}~\Omega \)
Subtopic:  Conversion to Ammeter & Voltmeter |
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