Question 21:
difficultA current I flows around a closed path in the horizontal plane of the circle as shown in the figure. The path consists of eight arcs with alternating radii r and 2r. Each segment of arc subtends equal angle at the common centre P. The magnetic field produced by current path at point P is
Question 22:
easyIf a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be :
Inside the pipe current enclosed will be zero so magnetic field will also be zero. Outside the pipe there will be net Magnetic field
Question 23:
easyIn a co-axial straight cable, the central conductor and the outer conductor have equal currents in opposite directions. The magnetic induction is zero :
As outside the conductor net current enclosed is zero. using ampere circuital law Magnetic field is also zero.
Question 24:
easyA solenoid consists of 100 turns of wire and has a length of 10.0cm. The magnetic field inside the solenoid when it carries a current of 0.500 A will be :
\[Â B= \mu_{0}ni \] where n is number of turns per unit length
n= 100/0.1=1000
i=0.5
substituting we get \[ B = 6.28\times 10^{-4} T\]
Question 25:
moderateIn the adjacent figure is shown a closed path P. A long straight conductor carrying a current I passes through O and perpendicular to the plane of the paper. Then which of the following holds good ?
As Current enclosed is zero. \[\int_{P}^{}\overrightarrow{B}.\overrightarrow{dl}=0\]
Question 26:
moderateA bar magnet of length ‘l’ and magnetic dipole moment ‘M’ is bent in the form of an arc as
shown in figure. The new magnetic dipole moment will be :
Question 27:
difficultA plastic disc of radius R has a charge q uniformly distributed over its surface. If the disc is rotated with a frequency f about its axis. then magnetic dipole moment will be :
Question 28:
moderateA loop carrying current I lies in the x–y plane as shown in the figure. The unit vector ˆk is coming out of the plane of the paper. The magnetic moment of the current loop is :
Question 29:
easyTwo particles X and Y having equal charges, after being accelerated through the same potential
difference, enter a region of uniform magnetic field and describe circular paths of radii R1 and
R2 respectively. The ratio of masses of X and Y is :
Question 30:
easyA beam of electrons is projected horizontally to the right. A straight conductor carrying a current is supported parallel to the electron beam and above it. If the current in the conductor is from left to right, what will be the effect on the electron beam ?