Which charge configuration produces a uniform electric field?

(a)

point charge

(b)

uniformly charged infinite line

(c)

uniformly charged infinite plane

(d)

uniformly charged spherical shell

What will happen if two conducting spheres are separately charged and then brought in contact?

(a)

Total charge on the two spheres is conserved

(b)

The total energy is conserved

(c)

Both charge and energy are conserved

(d)

The final potential is the mean of the original potentials.

In a parallel plate capacitor of capacitance C, a metal sheet is inserted between the plates, parallel to them. The thickness of the sheet is half of the separation between the plates. The capacitance now becomes

(a)

2C

(b)

\(\frac{C}{4}\)

(c)

4C

(d)

\(\frac{C}{2}\)

A charge q₁ exerts force on charge q₂. If another charge q₃ is brought near, the force of q₁, exerted on q₂, will be

(a)

decreased

(b)

increased

(c)

remains unchanged

(d)

increased if q₃ is of same sign as q₁ and decreased if q₂ is of opposite sign.

By using law of conservation of electric charge balance the following equations:
₉₂U²³⁸ ⇾ ₉₀Th²³⁴ +________.

(a)

₂He⁴

(b)

₁H³

(c)

₁H²

(d)

₁H¹

What is the value of resistance of the following resistor?

(a)

100 k Ω

(b)

10 k Ω

(c)

1 k Ω

(d)

1000 k Ω

When 'n' resistors of equal resistance (R) are connected in series and in parallel respectively, then the ratio of their effective resistance is ______________

(a)

1: n²

(b)

n²: 1

(c)

n: 1

(d)

1: n

The current in the given circuit is __________________.

(a)

\(\cfrac { 1 }{ 8 } A\)

(b)

\(\cfrac { 2 }{ 9 } A\)

(c)

\(\cfrac { 2 }{ 9 } A\)

(d)

\(1A\)

The value of current I in the network as shown is

(a)

\(\cfrac { 1 }{ 9 } A\)

(b)

\(\cfrac { 2 }{ 9 } A\)

(c)

\(\cfrac { 3 }{ 9 } A\)

(d)

1A

The curve representing Ohm's law is a ________________.

(a)

linear

(b)

parabola

(c)

hyperbola

(d)

none of the above

A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively. The magnetic induction at the centre of the spiral is ______.

(a)

\(5\mu T\)

(b)

\(7\mu T\)

(c)

\(8\mu T\)

(d)

\(10\mu T\)

An electron of mass 0.90 x 10^-30kg under the action of a magnetic field moves in a circle of 2cm radius at a speed of 3 x 10⁶ m/s if a proton of mass 1.8 x 10^-27 kg was to move in a circle of the same radius in the same magnetic field, then its speed will be _______________.

(a)

3.0 x 10⁶ m/s

(b)

1.5 x 10³ m/s

(c)

6.0 x 10⁴ m/s

(d)

cannot be estimated from the same data

The flux linked with a coil at any instant t is given by \(\Phi\)_B = 10t² − 50t + 250. The induced emf at t = 3s is

(a)

−190 V

(b)

−10 V

(c)

10 V

(d)

190 V

In Fleming's right hand rule, the forefinger represents the direction of ____________.

(a)

motion of the conductor

(b)

magnetic field

(c)

induced current

(d)

induced emf

The phase difference between VL and Vc is _________________

(a)

2π

(b)

π/2

(c)

π/4

(d)

π

The electric and the magnetic fields, associated with an electromagnetic wave, propagating along negative X axis can be represented by _____.

(a)

\(\vec { E } ={ E }_{ 0 }\hat { i } \) and \(\vec { B } ={ B }_{ 0 }\hat { k } \)

(b)

\(\vec { E } ={ E }_{ 0 }\hat { k } \) and \(\vec { B } ={ B }_{ 0 }\hat { j } \)

(c)

\(\vec { E } ={ E }_{ 0 }\hat { i } \) and \(\vec { B } ={ B }_{ 0 }\hat { j } \)

(d)

\(\vec { E } ={ E }_{ 0 }\hat { j } \) and \(\vec { B } ={ B }_{ 0 }\hat { i } \)

Which EM waves are used in medicine to destroy cancer cells?

(a)

radio waves

(b)

IR

(c)

૪ rays

(d)

UV rays

Which one of the following groups of electromagnetic waves is in order of increasing frequency?

(a)

Microwaves U-V rays, X-rays

(b)

Radio waves, visible light and 1-R rays

(c)

gamma rays U-V rays radio waves

(d)

gamma rays, U-V rays radio waves

If the velocity and wavelength of light in air is V_a and λ_a and that in water is V_w and λ_w, then the refractive index of water is______.

(a)

\(\frac{V_W}{V_a}\)

(b)

\(\frac{V_a}{V_W}\)

(c)

\(\frac{\lambda_W}{\lambda_a}\)

(d)

\(\frac{{V_a}\lambda_a}{{V_W}\lambda_W}\)

Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is _____.

(a)

\(\frac { hc }{ \lambda } -{ m }_{ e }+\frac { e^{ 2 }{ B }^{ 2 }{ R }^{ 2 } }{ { 2m }_{ e } } \)

(b)

\(\frac { hc }{ \lambda } +{ 2m }_{ e }{ \left[ \frac { eBR }{ { 2m }_{ e } } \right] }^{ 2 }\)

(c)

\(\\ \frac { hc }{ \lambda } -{ m }_{ e }{ c }^{ 2 }-\frac { e^{ 2 }{ B }^{ 2 }{ R }^{ 2 } }{ { 2m }_{ e } } \)

(d)

\(\frac { hc }{ \lambda } -{ 2m }_{ e }{ \left[ \frac { eBR }{ { 2m }_{ e } } \right] }^{ 2 }\)

Sodium and copper have work functions of 2.3eV and 4.5eV respectively, then the ratio of the wavelengths is nearest to ___________.

(a)

1: 2

(b)

4: 1

(c)

2: 1

(d)

1: 4

The minimum potential given to the anode for which the photoelectric current becomes zero is called _______ potential.

(a)

cut-off

(b)

threshold

(c)

saturation

(d)

active

A radiative element has N₀ number of nuclei at t = 0. The number of nuclei remaining after half of a half-life _____.(that is, at time t = \(\frac{1}{2}T_\frac{1}{2}\))

(a)

\(\frac{N_0}{2}\)

(b)

\(\frac{N_0}{\sqrt2}\)

(c)

\(\frac{N_0}{4}\)

(d)

\(\frac{N_0}{8}\)

Which one of the following represents forward bias diode?

(a)

(b)

(c)

(d)

“Sky wax” is an application of nano product in the field of _____.

(a)

Medicine

(b)

Textile

(c)

Sports

(d)

Automotive industry