Magnetic Lorentz force makes a moving charged particle to follow a _______

1. linear path

2. parabolic path

3. elliptical path

4. circular path

Unit of peltier coefficient is

1. ohm

2. mho

3. volt

4. ampere

In which of the following pairs of metals of the thermocouple, the emf is maximum?

1. Fe-Cu

2. Cu-Zn

3. Pt-Ag

4. Sb-Bi

Kirchhoff's I law is named as_____________

1. ohm's law

2. voltage law

3. resistance law

4. current law

In ' N-P-N transistor circuit, the emitter collector and base current are respectively I_E , I_C and I_B. The relation between them is

1. l_C < I_E < I_B

2. l_B < l_C< I_E

3. I_B > I_C> I_E

4. I_B > l_C > I_E

Which of the following is not a moderactor?

1. liquid sodium

2. ordinary water

3. graphite

4. heavy water

Five 3 resistances are arranged in a polygon (5 sides). What is the resistance between any two corners?

1. \(2.4\Omega \)

2. \(3\Omega \)

3. \(9\Omega \)

4. \(5\Omega \)

The potential gradient of the potentiometer wire depends on

1. only on the current that flows

2. only on the resistance per unit length of the wire

3. both the above mentioned

4. none ofthe above

Near a charged object A another earthed object B is placed. Charges are induced on B. If B is removed. After that the charge on A ________.

1. remains the same

2. decreases

3. increases

4. becomes zero

If the velocity and wavelength of light in air is v_a and \(\lambda _a\) and that in water is v_w and \(\lambda _w\) then the refractive index of water is, 

1. \(\frac { { V }_w }{ { V }_{ a } } \)

2. \(\frac { { V }_a }{ { V }_{ w } } \)

3. \(\frac { \lambda _{ w } }{ { \lambda }_{ a } } \)

4. \(\frac { { V }_{ a }\lambda _{ w } }{ { { V }_{ w }\lambda }_{ a } } \)

Device used for storing charges is __________.

1. resistor

2. capacitor

3. inductor

4. insulator

Which of the following has negative temperature coefficient of resistance?

1. copper

2. tungsten

3. carbon

4. silver

The charge of an electron is _______.

1. 1.66 X 10^-27 C

2. 1.602 X 10^-19 C

3. 1.602 x 10¹⁹ C

4. 1.612 x 10^-20 C

When three resistors are connected in series then the value of the effective resistance is

1. less than the individual resistance

2. greater than the individual resistance

3. greater than or equal to individual resistance

4. less than or equal to individual resistance

The nucleus is approximately spherical in shape. Then the surface area of nucleus having mass number A varies as.

1. A^2/3

2. A^4/3

3. A^1/3

4. A^5/3

Which of the following electromagnetic waves has the highest frequency?

1. radio waves

2. micro waves

3. X- rays

4. ૪-rays

The magnitude of electric dipole moment of water molecule is

1. 6 x 10^-30 cm

2. 6.2 x 10^-30 cm

3. 6.1 x 10^-30

4. 5.95 10^-30 cm

In a tangent galvanometer a current 1A, produces deflection of 30° the current required to produce a deflection of 60° is

1. 3A

2. 2A

3. \(\sqrt { 2 } \)

4. \(\frac { 1 }{ \sqrt { 3 } } \)A

If c is the velocity, v the frequency and \(\lambda\), the wavelength of a radiation, then its frequency is defined as

1. v = \(\frac {\lambda}{c}\)

2. n = c\(\lambda\)

3. v = \(\frac {c}{\lambda}\)

4. n = c - \(\lambda\)

A wire of resistance 2 ohms per meter is bent to form a circle of radius 1m. Th e equivalent resistance between its two diametrically opposite points, A and B as shown in the fi gure is

1. \(\pi \Omega\)

2. \(\frac{\pi}{2}\Omega\)

3. 2\(\pi \Omega\)

4. \(\frac{\pi}{4}\Omega\)

First diffraction minimum due to a single slit of width 1.0 x 10^-5 cm is at 30°. Then wavelength of light used is,

1. 400\(\mathring { A } \)

2. 500\(\mathring { A } \)

3. 600\(\mathring { A } \)

4. 700\(\mathring { A } \)

_______ are used as a diagnostic tool in medicine.

1. visible light

2. UV rays

3. X-rays

4. Gamma rays

Two radiations with photon energies 0.9 e V and 3.3 e V respectively are falling on a metallic surface successively. If the work function of the metal is 0.6 e V, then the ratio of maximum speeds of emitted electrons will be

1. 1:4 

2. 1:3 

3. 1:1

4. 1:9

To obtain sustained oscillation in an oscillator,

1. Feedback should be·positive 

2. Feedback factor must be unity 

3. Phase shift must be 0 or 2\(\pi\)

4. All the above 

Energy gap between valence band and conduction band is called as the _________

1. forbidden energy gap 

2. conduction band gap 

3. valence band gap

4. filled band gap 

Ohm's law is applicable only for_______________

1. complicated circuits

2. primary circuits

3. simple circuits

4. secondary circuits

The dipole is called point dipole when the distance

1. 2a approaches infinity and q approaches zero

2. 2a approaches zero and q approaches infinity

3. 2a approaches zero and q approaches zero

4. 2a approaches infinity and q approaches infinity

An electron moves straight inside a charged parallel plate capacitor of uniform charge density σ. Th e time taken by the electron to cross the parallel plate capacitor when the plates of the capacitor are kept under constant magnetic fi eld of induction \(\vec { B } \)is

 

1. \({ \varepsilon }_{ ° }\frac { eIB }{ \sigma } \)

2. \({ \varepsilon }_{ ° }\frac { IB }{ \sigma {I} } \)

3. \({ \varepsilon }_{ ° }\frac { IB }{ {e}\sigma } \)

4. \({ \varepsilon }_{ ° }\frac { IB }{ \sigma } \)

In Millikan's experiment, the plates are kept at a distance of 16mm and are maintained at a poential difference of 10,000 V. The electric intensity is

1. 62.5 V/m

2. 6.25 x 10⁵ V/m

3. 6.25 x 10³ V/m

4. 1.6 x 10⁵ V/m

A condenser is charged to a potential of 200V and has a charge of 0.1C. The energy stored in it is

1. 1 J

2. 2 J

3. 10 J

4. 20 J

The rays used in weather forecasting is ___________.

1. I-R rays

2. U-V rays

3. X - rays

4. μ-Waves

Fuse wire

1. is an alloy oflead and copper

2. has low resistance

3. has high resistance

4. has high melting point

The charge of cathode rays is 

1. positive 

2. negative

3. neutral 

4. not defined 

A virtual image three times the size of the object is obtained with a concave mirror of radius of curvature 36 cm. The distance of the object from the mirror is 

1. 5 cm

2. 12 cm

3. 10 cm

4. 20 cm

The unit for electric susceptibility is
 

1. Nm² C^-2 

2. C² N^-1 m^-2 

3. C^-2Nm² 

4. N^-1 m^-2C²

The electric field intensity at a short distance r from uniformly charged infinite plane sheet of charge is

1. proportional to r

2. proportional to \(\frac{1}{2}\)

3. proportional to \(\frac{1}{r^2}\)

4. independent of r

The splitting of spectral lines, when the atom is acted upon by a magnetic field is called __________ effect.

1. Bohr

2. Planck

3. Stark

4. Zeeman

A boy stands straight infront of a mirror at a distance of 30 cm away from it. He sees his erect image whose height is \(\frac { { 1 }^{ th } }{ 5 } \) of his real height. The mirror he is using is

1. plane mirror

2. convex mirror

3. concave lens 

4. plano-convex mirror

When the output is an complement of the input it is ___________.

1. NOT gate

2. AND gate 

3. OR

4. NAND 

The force between two charges in vacuum is 0.1N. What is the force if the vacuum is replaced by medium whose permittivity is 10 times greater than that of vacuum?

1. 0.1 N

2. 0.01 N

3. 0.001N

4. 0.0001 N

If the specific resistance of a potentiometer wire is 10^-7 Om and current flowing through it . is 0.1 amp, cross - sectional area of wire is 10^-6 m², then potential gradient will be

1. 10^-2 v/m

2. 10^-4 v/m

3. 10^-6 v/m

4. 10^-8v/m

A circular coil with a cross-sectional area of 4 cm² has 10 turns. It is placed at the centre of a long solenoid that has 15 turns/ cm and a cross-sectional area of 10 cm²• The axis of the coil coincides with the axis of the solenoid. What is their mutual inductance?

1. 7.54\(\mu \)H

2. 8.54\(\mu \)H

3. 9.54\(\mu \)H

4. 10.54\(\mu \)H

The light emitted in an LED is due to 

1. Recombination of charge carriers 

2. Reflection of light due to lens action 

3. Amplification of light falling at the junction

4. Large current capacity 

An ideal cell is connected to a capacitor through a voltmeter. The reading V of the voltmeter is plotted against time. Which of the following best represents the resulting curve?

1. 

2. 

3. 

4. 

If the potential difference between the cathode and the target of Coolidge tube is 1.24 x 10⁵V, then the minimum wavelength of continuous X-rays is _____.

1. 10 \(\mathring A\)

2. 1 \(\mathring A\)

3. 0.1 \(\mathring A\)

4. 0.01 \(\mathring A\)

For !oolean identities match the pair

1. \(\overset { = }{ A } \)              (P) \(\overline { A } \) + \(\overline { B } \)
2. \(\overline { A\ +\ B } \)     (Q) A . B
3. \(\overline { A\ .B } \)        (R) \(\overline { A } \) . \(\overline { B } \)
4. A. (\(\overline { A } \) + B)  (S) A

1. 1 - (S), 2 (P), 3 - (Q), 4 - (R)

2. 1- (S), 2 (R), 3 - (Q), 4 - (P)

3. 1- (S), 2 (Q), 3 - (P), 4 - (R)

4. 1 - (S), 2 (R), 3 - (P), 4 - (Q)

A potential of 1 kV is applied between the ends of conductor of length 20 cm. The drift velocity of electron in this field is 3.52 x 10⁶ m/s. The relaxation time for the freeelectrons is

1. 2 nano sec

2. 4 nano sec.

3. 6 nano sec

4. 8 nano sec.

A current gain for a transistor working as CB amplifier is 0.90. If emitter current is 10 mA, then base current is ______

1. 1 mA

2. 2 mA

3. 0.1 mA

4. 0.2 mA

The most suitable metal for permanent magnet is

1. copper

2. aluminium

3. steel

4. iron

In NPN transistors, when the emitter-base junction is forward-biased, the direction of conventional current is from __________

1. base to emitter 

2. emitterto base 

3. collector to base 

4. base to collector 

A radioactive nucleus (intial mass number A and atomic number Z) emits 2\(\alpha\) and 2 positrons. The ratio of neutrons to that of proton.The ratio of number of neutrons to that of proton in the final nucleus Will be   

1. \(\frac { A-Z-4 }{ Z-2 } \)

2. \(\frac { A-Z-2 }{ Z-6 } \)

3. \(\frac { A-Z-4 }{ Z-6 } \)

4. \(\frac { A-Z-12 }{ Z-4 } \)

The wavelength range of microwave is _______m

1. 10^-8 to 0.35

2. 10^-3 to 0.3

3. 10^-8 to 10^-6

4. 10^-3 to 10^-1

In an a.c generator, the brushes are made of __________

1. silicon

2. plastic

3. carbon

4. nylon

The first theoretical explanation superconductivity was given by_______

1. BSC theory

2. BCS theory

3. SBC theory

4. None

According to to Bohr, the relation between principal quantum number (n) and radius of the orbit (r) is

1. r \(\alpha\) \(\frac1n\)

2. r \(\alpha\) \(\frac{1}{n^2}\)

3. r \(\alpha\) n

4. r \(\alpha\) n²

In a hydrogen atom the electron revolves around the proton in an orbit of 0.53 \(\mathring { A } \). The potential produced by the electron on the nuleus is

1. 6.8 V 

2. 13.6 V

3. 54.4 V

    

4. 27.2 V

Resistance between the points A and B in the given figure is

1. \(9\Omega \)

2. \(2\Omega \quad \)

3. \(3\Omega \)

4. \(6\Omega \)

In Millikan's oil drop experiment, charged drop is balanced between the two plates. Now the viscous force

1. acts downwards

2. acts upwards

3. is zero

4. acts either upwards or downwards

In an experi,ment of find the focal length of a concave mirror a graph is drawn between the magnitudes of u and v. the graph looks like

1. 

2. 

3. 

4. 

The potentiometer wire is made of___________

1. Manganin

2. Copper

3. Aluminium

4. Nichrome

Semi-conductor has phosphorous as impurity then it will have ________

1. n_e >> n_h

2. n_e << n_h

3. n_e = n_h

4. n_e = n_h = n_i

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

1. each of them increases

2. each of them decreases

3. copper increases and germanium decreases

4. copper decreases and germanium increases

For a given thermocouple for a given cold junction temperature, the inversion is 220°C. When the cold junction temperature is increased by 20°C, then the inversion temperature is

1. 200°C

2. 220°C

3. 240°C

4. 110°C

The mass of a ₇³Li nucleus is 0.042 u less than the sum of the masses of all its nucleons. The binding energy per nucleon of ₇³Li nucleus is nearly

1. 46 MeV

2. 5.6 MeV

3. 3.9 MeV

4. 23 MeV

\(\alpha\)-rays consist of \(\alpha\)-particles, which are ___ nuclei.

1. hydrogen

2. helium

3. heavy water

4. boron

The operating point of an amplifier is also called as ___________

1. base point 

2. collector point 

3. emitter point 

4. quiescent point

Controlled chain reaction is seen in ______

1. atom bombs

2. nuclear reactors

3. synchrotron

4. detectors

If V_g, V_x' V_m are speeds of gamma rays, X rays and microwaves respectively in vacuum, then

1. V_g<V_x<V_m

2. V_g>V_k>V_m

3. V_g > V_x < V_m

4. V_g=V_x=V_m

The unit of Galvanometer constant is ________

1. Am^-1

2. A rad^-1

3. AC^-1

4. As^-1

 The variation of frequency of carrier wave with respect to the amplitude of the modulating signal is called ___________

1. Amplitude modulation 

2. Frequency modulation

3. Phase modulation 

4. Pulse width modulation