# +2 Physics Effects of Electric Current One Mark Questions

This section deals with One Mark Questions picked for Physics subject from Effects of electric Current chapter. Practice these sample questions well from an examination angle and if you know the answers to any of these questions, share it in the comments section of this blog.

1) Two electric bulbs whose resistances are in the ratio 1:2 are connected in parallel to a constant voltage source.
The amount of heat dissipated in them have the ratio:

a) 1:2                         b)1:1                         c)2:1                         d)1:4

2) The neutral temperature of a thermocouple is $275^{\circ}C$ and the temperature of inversion is $600^{\circ}C$. The temperature of cold junction is:

a) $-50^{\circ}C$     b) $-25^{\circ}C$     c) $25^{\circ}C$     d) $50^{\circ}C$

3) Which is independent of the temperature of the cold junction?

a) inversion temperature          b) neutral temperature          c) both inversion and neutral temperature

d) neither inversion nor neutral temperature

4) A long straight wire carrying current produces a magnetic induction $3\times 10^{-6}T$ at a point, 10 cm from the wire.
The current through the wire is:

a) 3A                        b) 6A                        c) 4.5A                        d) 1.5A

5) Two circular coils have number of turns in the ratio 1:2 and radii in the ratio 2:1.
If the same current flows through them, the magnetic fields at their centres the deflection will be:

a) 1:1                       b) 1:2                       c) 2:1                       d) 1:4

6) In a tangent galvanometer, for a constant current, the deflection is $30^{\circ}C$.
The plane of the coil is rotated through $180^{\circ}C$. Now for the same current the deflection will be:

a) $30^{\circ}C$     b) $60^{\circ}C$     c) $90^{\circ}C$     d) $0^{\circ}C$


7) A solenoid is 2m long and 1.5cm in radius. It has 5 layers of windings of 1000 turns each and carries a current of 10A.
The magnetic induction of its centre along its axis is:

a) $1.57\times 10^{-2}T$                         b) $3.14\times 10^{-2}T$

c) $6.28\times 10^{-2}T$                         d) zero

8) An $\alpha-$ particle enters a magnetic field of flux density $2.5 \;wb/m^{2}$ with a velocity of $2\times 10^{7}m/s$
at an angle of $30^{\circ}C$ with the field. The force on the particle will be:

a) $4\times 10^{-12}N$                                   b) $8\times 10^{-12}N$

c) $4\times 10^{12}N$                                    d) $8\times 10^{12}N$

9) An electron describes a circular orbit of radius of 2cm in a uniform magnetic field.
If the speed of the electron is doubled then the radius of the become:

a) 0.5 cm                b) 1.0 cm                c) 2.0 cm                d) 4.0 cm

10) A current of 10A is flowing in a wire of length 1.5m. A force of 15N acts on it when it is placed in a uniform magnetic filed of 2T.
The angle between the magnetic field and the direction of current is:

a) $30^{\circ}C$     b) $45^{\circ}C$     c) $60^{\circ}C$     d) $90^{\circ}C$

11) Two long parallel wires carry currents of 5A each in opposite directions.
If the wires are separated by distance of 0.5m, then the force between the two wires is:

a) $10^{-5}N$, attractive                                  b) $10^{-5}N$, replulsive

c) $2\times 10^{-5}N$, attractive                      d) $2\times 10^{-5}N$, repulsive

12) A galvanometer of a resistance $100\Omega$ gives full scale deflection with 5mA current.
In order to convert it into a 5V range voltmeter, the value of resistance connected in series is:

a) $900\Omega$     b) $10^{4}\Omega$     c) $999\Omega$     d) $1M\Omega$

13) To send 10% of the main current through a moving coil galvanometer of resistance $99\Omega$, the shunt required is:

a) $9.9\Omega$     b) $9\Omega$     c) $10\Omega$     d) $11\Omega$

14) When 2A current is passed through a tangent galvanometer, it gives a deflection of $30^{\circ}C$. For $60^{\circ}C$ deflection, the current must be:

a) 1A                           b) $2\sqrt{3} \;A$                           c) 4A                           d) 6A

15) A wire of length 2m carries a current of 1A is bend to form a circle. The magnetic moment of the coil is:

a) $2\pi \; Am^{2}$                                b) $\frac{\pi}{2} \; Am^{2}$

c) $\frac{\pi}{4} \; Am^{2}$                    d) $\frac{1}{\pi} \; Am^{2}$