The self inductance of a coil having 500 turns is 50 mH. The magnetic flux through the cross-sectional area of the coil while current through it is 8 mA is found to be

1. $4\times {10}^{-4} Wb$

2. $0.04 Wb$

3. $4\mu Wb$

4. 40 mWb

A uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature slightly, then

1. its speed of rotation increases

2. its speed of rotation decreases

3. its speed of rotation remains same

4. its speed increases because its moment inertia increases

A uniform disc is acted by two equal forces of magnitude R. One of them, acts tangentially to the disc, while other one is acting a the central point of the disc. The friction between disc surface and ground surface is nF. If r be the radius of the disc, then the value of n would be (in N)

1. 0

2. 1.2

3. 2.0

4. 3.2

While keeping area of cross-section of a solenoid same, the number of turns and length of solenoid one both doubled. The self inductance of the coil will be

1. halved

2. doubled

3. $\frac{1}{4}$ times the original value

4. unaffected 

Consider the circular loop having current I and with central point O. The magnetic field at the central point O is 
                                      

1. $\frac{2 {\mu }_0 i}{3 \mathrm{\pi } \mathrm{R}}$ acting downward

2. $\frac{5 {\mu }_0 i}{12 \mathrm{R}}$ acting downward

3. $\frac{6 {\mu }_0 i}{11 \mathrm{R}}$ acting downward

4. $\frac{3 {\mu }_0 i}{7 \mathrm{R}}$ acting downward

The Boolean expression , where P and Q are the inputs of the logic circuit, represents

1. AND gate

2. NAND gate

3. NOT gate

4. OR gate

Consider the diagram shown below. 
                       
A voltmeter of resistance 150 Ωis connected across A and B. The potential drop across B and C measured by voltmeter is

1. 33 V

2. 26 V

3. 31 V

4. 28 V

Two spherical nuclei have mass numbers 216 and 64 with their radii R₁ and R₂ respectively. The ratio,  \(R_1 \over R_2\) is equal to

1. 3:2 

2. 1:3

3. 1:2

4. 2:3

A massless rod S having length 2l has equal point masses attached of its tow ends as shown in the figure. The rod is rotating about an axis passing through its centre and making angle α with the axis. The magnitude of change of momentum of rod i.e. equals 

1. $2 m I^3 {\omega }^2 \sin \theta ·\cos \theta$

2. $m{I}^2 {\omega }^2 \sin 2\theta$

3. $m{I}^2 \sin 2\theta$

4. $m^{1/2}{I}^{1/2} \omega \sin \theta ·\cos \theta$

A semiconductor having electron and hole mobilities respectively. 
If its intrinsic carrier density is , then what will be the value of hole concentration P for which the conductivity will be minimum at a given temperature?

1. $ni\sqrt{\frac{{\mu }_n}{{\mu }_p}}$

2. $nh\sqrt{\frac{{\mu }_n}{{\mu }_p}}$

3. $ni\sqrt{\frac{{\mu }_p}{{\mu }_n}}$

4. $nh\sqrt{\frac{{\mu }_p}{{\mu }_n}}$