Three charges Q0, -q and -q are placed at the vertices of an isosceles right angle triangle as in the figure. The net electrostatic potential energy is zero if Q0 is equal to
+ q
The drift velocity of the electrons in a copper wire of length 2 m under the application of a potential difference of 220 V is 0.5 ms-1. Their mobility (in m2V-1s-1)
2.5 × 10-3
2.5 × 10-2
5 × 102
5 × 10-3
When two resistances R1 and R2 are connected in series, they consume 12 W power. When they are connected in parallel, they consume 50 W power. What the ratio of the powers of R1 and R2 ?
1/4
4
3/2
3
In the circuit shown, if the resistance 5 Ω develops a heat of 42 J per second, heat developed in 2 Ω must be about (in Js-1)
25
20
30
35
When a Daniel cell is connected in the secondary circuit of a potentiometer, the balancing length is found to be 540 cm. If the balancing length becomes 500 cm when the cell is short circuited with 1 Ω, the internal of the cell is
0.08 Ω
0.04 Ω
1.0 Ω
1.08 Ω
Two particles of equal charges after being accelerated through the same potential difference enter a uniform transverse magnetic field and describe circular path of radii R1 and R2 respectively. Then the ratio of their masses (M1/M2)
(M,/M,) i
Electromagnets are made of soft iron because soft iron has
low susceptibility and low retentivity
low susceptibility and high retentivity
high permeability and low retentivity
high permeability and high coercivity
Which one of the following characteristics is not associated with a ferromagnetic material ?
It is strongly attracted by a magnet
It tends to move from a region of strong magnetic field to a region of low magnetic field
Its origin is the spin of electrons
Above the Curie temperature, it exhibits paramagnetic properties
The oscillating frequency of a cyclotron is 10 MHz. If the radius of its dees is 0.5 m, the kinetic energy of a proton, which is accelerated by the cyclotron is
10.2 MeV
2.55 MeV
20.4 MeV
5.1 MeV
D.
5.1 MeV
KE of charged possible in a cyclotron,