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A current-carrying closed loop in the form of a right-angle isosceles triangle ABC is placed in a uniform magnetic field acting along AB. If the magnetic force on the arm BC is F, the force on the arm AC is:
In order to pass 10% of the main current through a moving coil galvanometer of 99 ohms, the resistance of the required shunt is:
A square loop, carrying a steady current I, is placed in a horizontal plane near a long straight conductor carrying a steady current I₁ at a distance d from the conductor as shown in figure. The loop will experience
The resistance of an ideal voltmeter is:
The energy equivalent of 0.5 g of a substance is:
A galvanometer having a resistance of $8\ \Omega$ is shunted by a wire of resistance $2\ \Omega$. If the total current is $1\ \text{A}$, the part of it passing through the shunt will be:
If an ammeter A reads 2 A and the voltmeter V reads 20 V, what is the value of resistance R? (Assuming finite resistances of ammeter and voltmeter)
A voltmeter has a range $V$ with a series resistance $R$. With a series resistance $2R$, the range is $V'$. The correct relation between $V$ and $V'$ is:
An electron moving in a circular orbit of radius r makes n rotations per second. The magnetic field produced at the centre has a magnitude:
The current flowing in a coil of resistance $90~\Omega$ is to be reduced by $90\%$. What value of resistance should be connected in parallel with it?
The nuclei $_{6}^{13}\text{C}$ and $_{7}^{14}\text{N}$ can be described as:
A galvanometer of $50~\Omega$ resistance has 25 divisions. A current of $4 \times 10^{-4} \text{ A}$ gives a deflection of one division. To convert this galvanometer into a voltmeter having a range of $25 \text{ V}$, it should be connected with a resistance of:
A beam of electrons passes un-deflected through mutually perpendicular electric and magnetic fields. Where do the electrons move if the electric field is switched off and the same magnetic field is maintained?
When a charged particle with velocity $\vec{v}$ is subjected to an induction magnetic field $\vec{B}$, the force on it is non-zero. What does this imply?
Two circular coils 1 and 2 are made from the same wire but the radius of the 1st coil is twice that of the 2nd coil. What is the ratio of the potential difference applied across them so that the magnetic field at their centres is the same?
A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the center of the loop is $B$. It is then bent into a circular coil of $n$ turns. The magnetic field at the centre of this coil of $n$ turns will be:
An electron is moving in a circular path under the influence of a transverse magnetic field of $3.57 \times 10^{-2}$ T. If the value of $e/m$ is $1.76 \times 10^{11}$ C/kg, the frequency of revolution of the electron is:
The radius of a nucleus of a mass number $A$ is directly proportional to:
Two similar coils of radius $R$ are lying concentrically with their planes at right angles to each other. The currents flowing in them are $I$ and $2I$, respectively. The resultant magnetic field induction at the centre will be:
If the half-life of a substance is $77 \text{ days}$ then its decay constant ($\text{days}^{-1}$) will be: