12583 + Mcqs in Physics Page 203 McqOptions

10101.	What will be the wave velocity, if the radar gives 54 waves per min and wavelength of the given wave is 10 m [RPET 2000]
A.	4 m/sec
B.	6 m/sec
C.	9 m/sec
D.	5 m/sec
Answer» D. 5 m/sec

Discussion

10102.	The thermal capacity of a body is 80 cal, then its water equivalent is [UPSEAT 2001]
A.	80 cal / gm
B.	8 gm
C.	80 gm
D.	80 kg
Answer» D. 80 kg

Discussion

10103.	A step up transformer has transformation ration 5 : 3. What is voltage in secondary if voltage in primary is 60 V [Pb. PET 2000]
A.	20 V
B.	60 V
C.	100 V
D.	180 V
Answer» D. 180 V

Discussion

10104.	In a transformer, the number of turns in primary coil and secondary coil are 5 and 4 respectively. If 240 V is applied on the primary coil, then the ratio of current in primary and secondary coil is [AFMC 1998; CPMT 2000; Pb. PET 2002]
A.	4 : 5
B.	5 : 4
C.	5 : 9
D.	9 : 5
Answer» B. 5 : 4

Discussion

10105.	Assertion : Separation of isotope is possible because of the difference in electron numbers of isotope. Reason : Isotope of an element can be separated by using a mass spectrometer. [AIIMS 1999]
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» F.

Discussion

10106.	If the density of the earth is doubled keeping its radius constant then acceleration due to gravity will be \[(g=9.8\,m/{{s}^{2}})\] [Pb. PMT 2002; Orissa 2002]
A.	\[19.6\,m/{{s}^{2}}\]
B.	\[9.8\,m/{{s}^{2}}\]
C.	\[4.9\,m/{{s}^{2}}\]
D.	\[2.45\,m/{{s}^{2}}\]
Answer» B. \[9.8\,m/{{s}^{2}}\]

Discussion

10107.	The value of ?g? at a particular point is \[9.8\,m/{{s}^{2}}\]. Suppose the earth suddenly shrinks uniformly to half its present size without losing any mass. The value of ?g? at the same point (assuming that the distance of the point from the centre of earth does not shrink) will now be [NCERT 1984; DPMT 1999]
A.	\[4.9\,m/{{\sec }^{2}}\]
B.	\[3.1\,m/{{\sec }^{2}}\]
C.	\[9.8\,m/{{\sec }^{2}}\]
D.	\[19.6\,m/{{\sec }^{2}}\]
Answer» D. \[19.6\,m/{{\sec }^{2}}\]

Discussion

10108.	The temperature at which the speed of sound in air becomes double of its value at \[{{0}^{o}}C\] is [AIEEE 2002]
A.	273K
B.	546K
C.	1092K
D.	0K
Answer» D. 0K

Discussion

10109.	\[{{v}_{1}}\] and \[{{v}_{2}}\] are the velocities of sound at the same temperature in two monoatomic gases of densities \[{{\rho }_{1}}\] and \[{{\rho }_{2}}\] respectively. If \[{{\rho }_{1}}/{{\rho }_{2}}=\frac{1}{4}\] then the ratio of velocities \[{{v}_{1}}\] and \[{{v}_{2}}\] will be [KCET 2000; AIIMS 2002; AFMC 2002]
A.	1 : 2
B.	4 : 1
C.	2 : 1
D.	1 : 4
Answer» D. 1 : 4

Discussion

10110.	A helium nucleus makes a full rotation in a circle of radius 0.8 metre in two seconds. The value of the magnetic field B at the centre of the circle will be [CPMT 1988; KCET 1998; UPSEAT 2001]
A.	\[\frac{{{10}^{-19}}}{{{\mu }_{0}}}\]
B.	\[{{10}^{-19}}{{\mu }_{0}}\]
C.	\[2\times {{10}^{-10}}{{\mu }_{0}}\]
D.	\[\frac{2\times {{10}^{-10}}}{{{\mu }_{0}}}\]
Answer» C. \[2\times {{10}^{-10}}{{\mu }_{0}}\]

Discussion

10111.	Assertion : Compression and rarefaction involve changes in density and pressure. Reason : When particles are compressed, density of medium increases and when they are rarefied, density of medium decreases.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10112.	Assertion : Ocean waves hitting a beach are always found to be nearly normal to the shore. Reason : Ocean waves are longitudinal waves.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» D. If the assertion and reason both are false.

Discussion

10113.	The velocity factor of a transmission line x. If dielectric constant of the medium is 2.6, the value of x is [AFMC 1995]
A.	0.26
B.	0.62
C.	2.6
D.	6.2
Answer» C. 2.6

Discussion

10114.	Who among the following scientists made the statement ?"Chemical change can produce electricity" [DCE 2004]
A.	Galvani
B.	Faraday
C.	Coulomb
D.	Thomson
Answer» B. Faraday

Discussion

10115.	The potential difference V and the current i flowing through an instrument in an ac circuit of frequency f are given by \[V=5\cos \omega \,t\] volts and I = 2 sin wt amperes (where w = 2pf). The power dissipated in the instrument is [CPMT 1977, 80; MP PET 1999]
A.	Zero
B.	10 W
C.	5 W
D.	2.5 W
Answer» B. 10 W

Discussion

10116.	A body, whose momentum is constant, must have constant [AIIMS 2000]
A.	Force
B.	Velocity
C.	Acceleration
D.	All of these
Answer» C. Acceleration

Discussion

10117.	Assertion : A negative acceleration of a body can be associated with a ?speeding up? of the body. Reason : Increase in speed of a moving body is independent of its direction of motion.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

10118.	Assertion : As the frictional force increases, the safe velocity limit for taking a turn on an unbanked road also increases. Reason : Banking of roads will increase the value of limiting velocity.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

10119.	A bomb of mass \[30kg\]at rest explodes into two pieces of masses \[18\,kg\] and \[12\,kg\]. The velocity of \[18\,kg\]mass is \[6\,m{{s}^{-1}}\]. The kinetic energy of the other mass is [CBSE PMT 2005]
A.	256 J
B.	486 J
C.	524 J
D.	324 J
Answer» C. 524 J

Discussion

10120.	A current carrying wire in the neighborhood produces [AFMC 1999]
A.	No field
B.	Electric field only
C.	Magnetic field only
D.	Electric and magnetic fields
Answer» D. Electric and magnetic fields

Discussion

10121.	The radius of the Bohr orbit in the ground state of hydrogen atom is 0.5 Å. The radius of the orbit of the electron in the third excited state of \[H{{e}^{+}}\] will be [MP PMT 2000]
A.	8 Å
B.	4 Å
C.	0.5 Å
D.	0.25 Å
Answer» C. 0.5 Å

Discussion

10122.	The diagram shows the path of four a-particles of the same energy being scattered by the nucleus of an atom simultaneously. Which of these are/is not physically possible [AMU (Med.) 2001]
A.	3 and 4
B.	2 and 3
C.	1 and 4
D.	4 only
Answer» E.

Discussion

10123.	The energy of electron in the nth orbit of hydrogen atom is expressed as \[{{E}_{n}}=\frac{-13.6}{{{n}^{2}}}eV\]. The shortest and longest wavelength of Lyman series will be [Pb. PET 2003]
A.	910 Å, 1213 Å
B.	5463 Å, 7858 Å
C.	1315 Å, 1530 Å
D.	None of these
Answer» B. 5463 Å, 7858 Å

Discussion

10124.	An air capacitor is connected to a battery. The effect of filling the space between the plates with a dielectric is to increase [MP PMT 1995]
A.	The charge and the potential difference
B.	The potential difference and the electric field
C.	The electric field and the capacitance
D.	The charge and the capacitance
Answer» E.

Discussion

10125.	Assertion : Transverse waves are not produced in liquids and gases. Reason : Light waves are transverse waves.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

10126.	Assertion : The velocity of sound increases with increase in humidity. Reason : Velocity of sound does not depend upon the medium.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» D. If the assertion and reason both are false.

Discussion

10127.	Assertion : Sound waves cannot propagate through vacuum but light waves can. Reason : Sound waves cannot be polarised but light waves can be polarised. [AIIMS 1998]
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

10128.	Assertion : A metallic shield in form of a hollow shell may be built to block an electric field. Reason : In a hollow spherical shield, the electric field inside it is zero at every point. [AIIMS 2001]
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10129.	The current is flowing in south direction along a power line. The direction of magnetic field above the power line (neglecting earth's field) is [Pb. PMT 2004; Kerala PMT 2004]
A.	South
B.	East
C.	North
D.	West
Answer» E.

Discussion

10130.	Two tuning forks when sounded together produced 4 beats/sec. The frequency of one fork is 256. The number of beats heard increases when the fork of frequency 256 is loaded with wax. The frequency of the other fork is [CPMT 1976; MP PMT 1993]
A.	504
B.	520
C.	260
D.	252
Answer» D. 252

Discussion

10131.	The energy of the highest energy photon of Balmer series of hydrogen spectrum is close to [UPSEAT 2004]
A.	13.6 eV
B.	3.4 eV
C.	1.5 eV
D.	0.85 eV
Answer» C. 1.5 eV

Discussion

10132.	A bomb of 12 kg divides in two parts whose ratio of masses is 1 : 3. If kinetic energy of smaller part is 216 J, then momentum of bigger part in kg-m/sec will be [RPET 1997]
A.	36
B.	72
C.	108
D.	Data is incomplete
Answer» B. 72

Discussion

10133.	Two moles of an ideal monoatomic gas at \[{{27}^{o}}C\] occupies a volume of V. If the gas is expanded adiabatically to the volume \[2V,\] then the work done by the gas will be \[[\gamma =5/3,\,R=8.31J/mol\,K]\] [RPET 1999]
A.	\[-2767.23J\]
B.	\[2767.23J\]
C.	\[2500J\]
D.	\[-2500J\]
Answer» C. \[2500J\]

Discussion

10134.	A capacitor of capacity \[C\] is connected with a battery of potential \[V\] in parallel. The distance between its plates is reduced to half at once, assuming that the charge remains the same. Then to charge the capacitance upto the potential \[V\] again, the energy given by the battery will be [MP PET 1989]
A.	\[C{{V}^{2}}/4\]
B.	\[C{{V}^{2}}/2\]
C.	\[3C{{V}^{2}}/4\]
D.	\[C{{V}^{2}}\]
Answer» E.

Discussion

10135.	Assertion : The television broadcasting becomes weaker with increasing distance. Reason : The power transmitted from TV transmitter varies inversely as the distance of the receiver
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» D. If the assertion and reason both are false.

Discussion

10136.	If the water falls from a dam into a turbine wheel 19.6 m below, then the velocity of water at the turbine is \[(g=9.8\,m/{{s}^{2}})\] [AIIMS 1998]
A.	9.8 m/s
B.	19.6 m/s
C.	39.2 m/s
D.	98.0 m/s
Answer» C. 39.2 m/s

Discussion

10137.	The potential energy of a weight less spring compressed by a distance a is proportional to [MP PET 2003]
A.	\[a\]
B.	\[{{a}^{2}}\]
C.	\[{{a}^{-2}}\]
D.	\[{{a}^{0}}\]
Answer» C. \[{{a}^{-2}}\]

Discussion

10138.	Assertion : In vacuum tubes (valves), vacuum is necessary for the movement of electrons between electrodes otherwise electrons collide with air particle and loses their energy. Reason : In semiconductors devices, external heating or vacuum is not required.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

10139.	Two concentric coplanar circular loops of radii \[{{r}_{1}}\] and \[{{r}_{2}}\] carry currents of respectively \[{{i}_{1}}\] and \[{{i}_{2}}\] in opposite directions (one clockwise and the other anticlockwise.) The magnetic induction at the centre of the loops is half that due to \[{{i}_{1}}\] alone at the centre. If \[{{r}_{2}}=2{{r}_{1}}.\] the value of \[{{I}_{2}}/{{I}_{1}}\] is [MP PET 2000]
A.	2
B.	1/2
C.	1/4
D.	1
Answer» E.

Discussion

10140.	Assertion : Snow is better insulator than ice. Reason : Snow contain air packet and air is good insulator of heat.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10141.	If radius of earth is R then the height ?h? at which value of ?g? becomes one-fourth is [BHU 2000]
A.	\[\frac{R}{4}\]
B.	\[\frac{3R}{4}\]
C.	R
D.	\[\frac{R}{8}\]
Answer» D. \[\frac{R}{8}\]

Discussion

10142.	Two capillary tubes of radii 0.2 cm and 0.4 cm are dipped in the same liquid. The ratio of heights through which liquid will rise in the tubes is [MNR 1998]
A.	1 : 2
B.	2 : 1
C.	1 : 4
D.	4 : 1
Answer» C. 1 : 4

Discussion

10143.	Eight drops of mercury of equal radii possessing equal charges combine to form a big drop. Then the capacitance of bigger drop compared to each individual small drop is [MP PET 1990; MNR 1987; MP PMT 2002, 03; Pb. PET 2004; J & K CET 2005]
A.	8 times
B.	4 times
C.	2 times
D.	32 times
Answer» D. 32 times

Discussion

10144.	Assertion : The resistivity of a semiconductor increases with temperature. Reason : The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing it's resistivity. [AIIMS 2003]
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» E. If assertion is false but reason is true.

Discussion

10145.	Assertion : A transistor amplifier in common emitter configuration has a low input impedence. Reason : The base to emitter region is forward biased. [AIIMS 2004]
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10146.	Assertion : In the following circuit the potential drop across the resistance is zero. Reason : The given resistance has low value.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

10147.	If a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be [CBSE PMT 1999; AFMC 1999; CPMT 1984, 2000; Pb. PET 2000; JIPMER 2002]
A.	Only inside the pipe
B.	Only outside the pipe
C.	Neither inside nor outside the pipe
D.	Both inside and outside the pipe
Answer» C. Neither inside nor outside the pipe

Discussion

10148.	A tuning fork and a sonometer wire were sounded together and produce 4 beats per second. When the length of sonometer wire is 95 cm or 100 cm, the frequency of the tuning fork is [MP PMT 1990]
A.	156 Hz
B.	152 Hz
C.	148 Hz
D.	160 Hz
Answer» B. 152 Hz

Discussion

10149.	Assertion : Terminal velocity is same as the critical velocity. Reason : The constant velocity of fall of a body through a viscous fluid is called terminal velocity.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» F.

Discussion

10150.	The acceleration due to gravity is g at a point distant r from the centre of earth of radius R. If \[r
A.	\[g\propto r\]
B.	\[g\propto {{r}^{2}}\]
C.	\[g\propto {{r}^{-1}}\]
D.	\[g\propto {{r}^{-2}}\]
Answer» B. \[g\propto {{r}^{2}}\]

Discussion

Explore topic-wise MCQs in Joint Entrance Exam - Main (JEE Main).

What will be the wave velocity, if the radar gives 54 waves per min and wavelength of the given wave is 10 m [RPET 2000]

The thermal capacity of a body is 80 cal, then its water equivalent is [UPSEAT 2001]

A step up transformer has transformation ration 5 : 3. What is voltage in secondary if voltage in primary is 60 V [Pb. PET 2000]

In a transformer, the number of turns in primary coil and secondary coil are 5 and 4 respectively. If 240 V is applied on the primary coil, then the ratio of current in primary and secondary coil is [AFMC 1998; CPMT 2000; Pb. PET 2002]

Assertion : Separation of isotope is possible because of the difference in electron numbers of isotope. Reason : Isotope of an element can be separated by using a mass spectrometer. [AIIMS 1999]

If the density of the earth is doubled keeping its radius constant then acceleration due to gravity will be \[(g=9.8\,m/{{s}^{2}})\] [Pb. PMT 2002; Orissa 2002]

The temperature at which the speed of sound in air becomes double of its value at \[{{0}^{o}}C\] is [AIEEE 2002]

A helium nucleus makes a full rotation in a circle of radius 0.8 metre in two seconds. The value of the magnetic field B at the centre of the circle will be [CPMT 1988; KCET 1998; UPSEAT 2001]

Assertion : Compression and rarefaction involve changes in density and pressure. Reason : When particles are compressed, density of medium increases and when they are rarefied, density of medium decreases.

Assertion : Ocean waves hitting a beach are always found to be nearly normal to the shore. Reason : Ocean waves are longitudinal waves.

The velocity factor of a transmission line x. If dielectric constant of the medium is 2.6, the value of x is [AFMC 1995]

Who among the following scientists made the statement ?"Chemical change can produce electricity" [DCE 2004]

The potential difference V and the current i flowing through an instrument in an ac circuit of frequency f are given by \[V=5\cos \omega \,t\] volts and I = 2 sin wt amperes (where w = 2pf). The power dissipated in the instrument is [CPMT 1977, 80; MP PET 1999]

A body, whose momentum is constant, must have constant [AIIMS 2000]

Assertion : A negative acceleration of a body can be associated with a ?speeding up? of the body. Reason : Increase in speed of a moving body is independent of its direction of motion.

Assertion : As the frictional force increases, the safe velocity limit for taking a turn on an unbanked road also increases. Reason : Banking of roads will increase the value of limiting velocity.

A bomb of mass \[30kg\]at rest explodes into two pieces of masses \[18\,kg\] and \[12\,kg\]. The velocity of \[18\,kg\]mass is \[6\,m{{s}^{-1}}\]. The kinetic energy of the other mass is [CBSE PMT 2005]

A current carrying wire in the neighborhood produces [AFMC 1999]

The radius of the Bohr orbit in the ground state of hydrogen atom is 0.5 Å. The radius of the orbit of the electron in the third excited state of \[H{{e}^{+}}\] will be [MP PMT 2000]

The diagram shows the path of four a-particles of the same energy being scattered by the nucleus of an atom simultaneously. Which of these are/is not physically possible [AMU (Med.) 2001]

The energy of electron in the nth orbit of hydrogen atom is expressed as \[{{E}_{n}}=\frac{-13.6}{{{n}^{2}}}eV\]. The shortest and longest wavelength of Lyman series will be [Pb. PET 2003]

An air capacitor is connected to a battery. The effect of filling the space between the plates with a dielectric is to increase [MP PMT 1995]

Assertion : Transverse waves are not produced in liquids and gases. Reason : Light waves are transverse waves.

Assertion : The velocity of sound increases with increase in humidity. Reason : Velocity of sound does not depend upon the medium.

Assertion : Sound waves cannot propagate through vacuum but light waves can. Reason : Sound waves cannot be polarised but light waves can be polarised. [AIIMS 1998]

Assertion : A metallic shield in form of a hollow shell may be built to block an electric field. Reason : In a hollow spherical shield, the electric field inside it is zero at every point. [AIIMS 2001]

The current is flowing in south direction along a power line. The direction of magnetic field above the power line (neglecting earth's field) is [Pb. PMT 2004; Kerala PMT 2004]

Two tuning forks when sounded together produced 4 beats/sec. The frequency of one fork is 256. The number of beats heard increases when the fork of frequency 256 is loaded with wax. The frequency of the other fork is [CPMT 1976; MP PMT 1993]

The energy of the highest energy photon of Balmer series of hydrogen spectrum is close to [UPSEAT 2004]

A bomb of 12 kg divides in two parts whose ratio of masses is 1 : 3. If kinetic energy of smaller part is 216 J, then momentum of bigger part in kg-m/sec will be [RPET 1997]

Two moles of an ideal monoatomic gas at \[{{27}^{o}}C\] occupies a volume of V. If the gas is expanded adiabatically to the volume \[2V,\] then the work done by the gas will be \[[\gamma =5/3,\,R=8.31J/mol\,K]\] [RPET 1999]

Assertion : The television broadcasting becomes weaker with increasing distance. Reason : The power transmitted from TV transmitter varies inversely as the distance of the receiver

If the water falls from a dam into a turbine wheel 19.6 m below, then the velocity of water at the turbine is \[(g=9.8\,m/{{s}^{2}})\] [AIIMS 1998]

The potential energy of a weight less spring compressed by a distance a is proportional to [MP PET 2003]

Assertion : In vacuum tubes (valves), vacuum is necessary for the movement of electrons between electrodes otherwise electrons collide with air particle and loses their energy. Reason : In semiconductors devices, external heating or vacuum is not required.

Assertion : Snow is better insulator than ice. Reason : Snow contain air packet and air is good insulator of heat.

If radius of earth is R then the height ?h? at which value of ?g? becomes one-fourth is [BHU 2000]

Two capillary tubes of radii 0.2 cm and 0.4 cm are dipped in the same liquid. The ratio of heights through which liquid will rise in the tubes is [MNR 1998]

Eight drops of mercury of equal radii possessing equal charges combine to form a big drop. Then the capacitance of bigger drop compared to each individual small drop is [MP PET 1990; MNR 1987; MP PMT 2002, 03; Pb. PET 2004; J & K CET 2005]

Assertion : The resistivity of a semiconductor increases with temperature. Reason : The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing it's resistivity. [AIIMS 2003]

Assertion : A transistor amplifier in common emitter configuration has a low input impedence. Reason : The base to emitter region is forward biased. [AIIMS 2004]

Assertion : In the following circuit the potential drop across the resistance is zero. Reason : The given resistance has low value.

If a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be [CBSE PMT 1999; AFMC 1999; CPMT 1984, 2000; Pb. PET 2000; JIPMER 2002]

A tuning fork and a sonometer wire were sounded together and produce 4 beats per second. When the length of sonometer wire is 95 cm or 100 cm, the frequency of the tuning fork is [MP PMT 1990]

Assertion : Terminal velocity is same as the critical velocity. Reason : The constant velocity of fall of a body through a viscous fluid is called terminal velocity.

The acceleration due to gravity is g at a point distant r from the centre of earth of radius R. If \[r