CBSE
Multiple Choice QuestionsThe certain amount of current when flowing in a properly set tangent galvanometer produces a deflection of 45°. The current be reduced by a factor of ✓3, the deflection would :
decrease by 30°
decrease by 15°
increase by 15°
increase by 30°
A uniform magnetic field is at a right angle to the direction of motion of proton. As a result, the proton describes a circular path of radius 2.5 cm. If the speed of proton is doubled then the radius of the circular path will be :
0.5 cm
2.5 cm
5.0 cm
7.5 cm
An electron, moving in a uniform magnetic field of induction of intensity B, has its radius directly proportional to:
its charge
magnetic field
speed
none of these
An electron accelerated through a potential difference enters into a uniform transverse magnetic field and experience a force F. If the accelerating potential is increased to 2V, the electron in the same magnetic field will experience a force :
F
F/2
2F
A small circular flexible loop of wire of radius 'r' carries a current I. It is placed in a uniform magnetic field B. The tension in the loop will be doubled if :
I is doubled
B is halved
r is doubled
Both B and I are doubled
In a cyclotron, if a deuteron can gain the energy of 40 MeV, then a proton can gain the energy of:
40 MeV
80 MeV
20 MeV
60 MeV
Which of the following has the minimum resistance?
Voltmeter
Millivoltmeter
Ammeter
Milliameter
Two parallel wires carrying current in the same direction attract each other because of :
the potential difference between them
mutual inductance between them
the electric force between them
the magnetic force between them
A wire carrying current I and other carrying 2I in the same direction produce a magnetic field B at the mid-point. What will be the field when 2I wire is switched off?
B/2
2B
B
4B
A galvanometer has a resistance of 400 Ω and deflects full scale for a current of 0.2 mA through it. The shunt resistance required to covert it into 3A ammeter is :
0.027 Ω
0.054 Ω
0.0135 Ω
none of these
