Recent questions tagged exemplar

List the changes observed in an angiosperm flower subsequent to pollination and fertilization.

asked Jun 12, 2017 by pady_1

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List the changes observed in an angiosperm flower subsequent to pollination and fertilization.

asked Jun 12, 2017 by pady_1

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Is it possible to consider vegetative propagation observe in certain plants like Bryophyllum, water

asked Jun 12, 2017 by pady_1

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With which type of reproduction do we associate the reduction division ? Analyse the reasons for it.

asked Jun 12, 2017 by pady_1

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The number of texa exhibiting asexual reproduction is drastically reduced in higher plants (ang

asked Jun 12, 2017 by pady_1

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Which of the following are monoeciuos and dieocious organisms?

asked Jun 11, 2017 by pady_1

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Give reasons as to why cell division cannot be a type of reproduction in multicellular organism.

asked Jun 11, 2017 by pady_1

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Is there a relationship between the size of an organism and its life span ? Give two examples in sup

asked Jun 11, 2017 by pady_1

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Rearrange the following events of sexual reproduction in the sequence in which they occur in a flowe

asked Jun 11, 2017 by pady_1

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Although potato tuber is an underground part, it is considered as a stem. Give two reasons.

asked Jun 11, 2017 by pady_1

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In haploid organism that undergo sexual reproduction, name the stage in the life cycle when meiosis

asked Jun 11, 2017 by pady_1

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What do the following parts of a flower develop into after fertilization ?

asked Jun 11, 2017 by pady_1

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In haploid organism that undergo sexual reproduction, name the stage in the life cycle when meiosis

asked Jun 11, 2017 by pady_1

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Between an annual and a perennial plant, which one has a shorter juvenile phase? Give one reaso

asked Jun 11, 2017 by pady_1

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Explain the structure of a typical angiospermic anther.

asked Jun 9, 2017 by pady_1

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Why do we refer to offspring formed by asexual method of reproduction as clones ?

asked Jun 9, 2017 by pady_1

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Mention two inherent characteristics of Amoeba and yeast that enable them to reproduce ase

asked Jun 9, 2017 by pady_1

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A parallel plate capacitor is made of two dielectric blocks in series. One of the blocks has thickness $d_1$ and dielectric constant $k_1$ and the other has thickness $d_2$ and dielectric constant $k_2$ as shown in Fig. This arrangement can be thought as a dielectric slab of thickness $d (= d_1+d_2)$ and effective dielectric constant k. The k is

asked Jan 3, 2017 by meena.p

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Explain what would happen if in the capacitor given in 3 mm thick mica sheet (of dielectric constant = 6) were inserted between the plates C=1.771 x 10^-11 F, after the supply voltage of 100 V is was disconnected

asked Jan 2, 2017 by meena.p

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Explain what would happen if in the capacitor given in 3 mm thick mica sheet (of dielectric constant = 6) were inserted between the plates, While the voltage supply remained connected.

asked Jan 2, 2017 by meena.p

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If each diode in the figure has a forward bias resistance of $25\;\Omega$ and infinite resistance in reverse bias , What will be the values of the current $I_1, I_2, I_3$ and $I_4$ ?

asked Jan 2, 2017 by meena.p

1 answer

A zener of power rating 1W is to be used as a voltage regulator . If Zener has a breakdown of $5V$ and it has to regulate the voltage which fluctuated between $3\;V$ and $7\;V$, What should be the value of $R_s$ for Safe operation .

asked Jan 2, 2017 by meena.p

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In the circuit shown in the figure , if the diode forward voltage is $0.3\;V$ , the voltage difference between A and B is

asked Jan 1, 2017 by meena.p

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ODBAC is a fixed rectangular conductor of negligible resistance (co is not connected) and OP is a conductor which rotates clockwise with an angular velocity $w$ as shown in the fig. The entire system is in a uniform magnetic field B whose direction is along the normal to the surface of the rectangular conductor ABDC. The conductor OP is in electric contact with ABDC. The rotating conductor has resistance of X per unit length. Find the current in the rotating conductor as it rotates by $180^{\circ}$

asked Jan 1, 2017 by priyanka.c

1 answer

A conducting wire XY of mass $m$ and negligible resistance slides smoothly on two parallel conducting wire as shown in the fig. The closed circuit has a resistance R due to AC. AB and CD are perfect conductors. There is a magnetic field $B = B (+) \hat {k}$ . Is there a decrease in kinetic energy of XY equalling the heat lost in R ?

asked Jan 1, 2017 by priyanka.c

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A conducting wire XY of mass $m$ and negligible resistance slides smoothly on two parallel conducting wire as shown in the fig. The closed circuit has a resistance R due to AC. AB and CD are perfect conductors. There is a magnetic field $B = B (+) \hat {k}$ If B is independent of time, obtain $V (t)$ assuming $V(0) = u_0$

asked Jan 1, 2017 by priyanka.c

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A magnetic field $B =B_o \sin(wt) \hat{k}$ covers a large region where a wire AB slides smoothly over two parallel conductors separated by a distance d, as shown in the fig. The wire are in the x-y plane. The wire AB (of length d) has resistance R and the parallel wires have negligible resistance. It AB is moving velocity $v$, what is the force needed to keep the wire at constant velocity ?

asked Jan 1, 2017 by priyanka.c

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A conducting wire XY of mass $m$ and negligible resistance slides smoothly on two parallel conducting wire as shown in the fig. The closed circuit has a resistance R due to AC. AB and CD are perfect conductors. There is a magnetic field $B = B (+) \hat {k}$ write down the equation for the acceleration of the wire XY.

asked Jan 1, 2017 by priyanka.c

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Consider a metal ring kept (supported by a cardboard) on top of a fixed solenoid carrying a current $I$ as shown in the fig : The centre of the ring coincides with the axis of the solenoid. If the current in the solenoid is switched off, What happens to the ring ?

asked Jan 1, 2017 by priyanka.c

1 answer

Consider a metal ring kept on top of a fixed solenoid (say on a cardboard) as shown in the figure. The centre of the ring coincides with the axis of the solenoid. If the current is suddenly switched on, the metal ring jumps up. Explain.

asked Dec 31, 2016 by priyanka.c

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A solenoid is connect to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, will the current increases or decreases ? Explain ?

asked Dec 31, 2016 by priyanka.c

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A wire in the form of a tightly wound solenoid is connected to DC source, and carries a current. If the coil is stretched so that spiral coil, will the current increases or decreases ? Explain.
(a) the current drawn from the d.c source increases
(b) the current drawn from d.c source decreases
(c) the current drawn first increases and then decreases
(d) the current drawn first decreases and then increases

asked Dec 31, 2016 by priyanka.c

1 answer

Consider a magnet surrounded by a wire with an on/off switch as shown in the fig. If the switch is thrown from the off position (open circuit) to the on position (closed circuit) will a current flow in the circuit ? Explain.
(a) Yes
(b) No
(c) Cannot be determine
(d) information not sufficient

asked Dec 31, 2016 by priyanka.c

1 answer

A circular coil expands radially in a region of magnetic field and no electromotive force is produced in the coil. The can be cause
(a) The magnetic field is constant
(b) The magnetic field is in the same plane as the circular coil and it may or may not vary
(c) The magnetic field has a perpendicular (to the plane of the coil) component whose magnitude is decreasing suitably.
(d) There is constant magnetic field in the perpendicular (to the plane of the coil) direction

asked Dec 31, 2016 by priyanka.c

1 answer

The mutual inductance $M_{12}$ of coil 1 with respect to coil 2.

asked Dec 31, 2016 by priyanka.c

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An emf is produced in a coil, which is not connected to an external voltage source. This can be due to <br/(a) the coil being in a time varying magnetic field
(b) the coil moving in a time varying magnetic field
(c) the coil moving in a constant magnetic field
(d) the coil is stationary in external spatially varying magnetic field, which does not change with time.

asked Dec 31, 2016 by priyanka.c

1 answer

An $emf$ is produced in a coil, which is not connected to an external voltage source. This can be due to
(a) The coil being in a time varying magnetic field
(b) The coil moving in a time varying magnetic field
(c) The coil moving in a constant magnetic field
(d) The coil is stationary is externally spatially varying magnetic field, which does not change with time.

asked Dec 31, 2016 by priyanka.c

1 answer

A metal plate is getting heated. It can be because of
(a) a direct current is passing through the plate.
(b) it is placed in a times varying magnetic field
(c) it is placed in a space varying magnetic field but does not varying with time
(d) a current (either direct or alternating ) is passing through the plate.

asked Dec 31, 2016 by priyanka.c

1 answer

The self inductance L of a solenoid of length $l$ and area of cross section A, with a fixed number of turns N increases as

asked Dec 31, 2016 by priyanka.c

1 answer

There are two coils A and B. A current starts flowing in B, the coil A is made to rotate about a vertical axis as shown in the fig. No current flows in B if A is at rest. The current in the coil A, when the current in B (at t = 0) is counter clockwise and the coil A is as shown at this instant t= 0 is
(a) constant current clockwise
(b) varying current clockwise
(c) varying current clockwise<br> (d) constant current counter clockwise.

asked Dec 31, 2016 by priyanka.c

1 answer

Equipotentials at a great distance from a collection whose total sum is not zero are approximately

asked Dec 31, 2016 by meena.p

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The electrostatic potential on the surface of a charged conducting sphere is $100\;V$ . Two statements are made in this regard: S1: At any point inside the sphere , electric intensity is zero . S2: At any point inside the sphere ,the electro potential is 100 V. Which of the following is a correct statement ?

asked Dec 31, 2016 by meena.p

1 answer

Figure shows some equipotential lines distributed in space .A charged object is moved from point A and point B.

asked Dec 31, 2016 by meena.p

1 answer

A positively charged particle is released from rest in an unifrom electric field . The electric potential energy of the charge

asked Dec 31, 2016 by meena.p

1 answer

There are two coils A and B as shown in fig. A current starts flowing in B as shown, when A is moved towards B and stops when A stops moving. The current in A is counter-clockwise. B is kept stationary when A moves. We can infer that
(a) there is a constant current in the anticlockwise direction in A (b) there is a varying current in A
(c) there is no current in A
(d) there is a constant current in the counter clockwise direction in A

asked Dec 31, 2016 by priyanka.c

1 answer

A capacitor of $4 \;\mu F$ is connected as shown in the figure . The internal resistance of the battery is $5.0 \Omega$ . The amount of charge on the capacitor plates will be

asked Dec 31, 2016 by meena.p

1 answer

A cylindrical bar magnet is rotated about its axis, as shown in fig. A wire is connected from the axis and is made to touch the cylindrical surface through a contact. Then
(a) a direct current flows in the ammeter A
(b) an alternating sinusoidal current flows through the ammeter A with a time period $T= \frac{2T}{w}$
(c) no current flows through the ammeter A
(d) a time varying non-sinusoidal current flows through the ammeter A

asked Dec 31, 2016 by priyanka.c

1 answer

A loop, made of straight edges has six corner at A(0, 0, 0), B(L, 0, 0), C(L, L, O), D(O, L,O), E(O, L, L) and F (0, 0, L). A magnetic field $B = B_o(\hat{i} + \hat{k})T$ is present in the region.
The flux passing through the loop ABCDEFA (in that order) is $(a)B_oL^2Wb$ $(b)2B_oL^2Wb$ $(c)\sqrt 2B_oL^2Wb$ $(d)4B_oL^2Wb$

asked Dec 31, 2016 by priyanka.c

1 answer

What happens during regulation action of a Zenerdiode ?

asked Dec 31, 2016 by meena.p

1 answer

A square of side L metres lies in the x-y plane in a region, where the magnetic field is given by $B = B_o (2 \hat{i} +3 \hat{j} + 4 \hat{k}) T,$ where $B_o$ is constant. The magnitude of flux passing through the square $(a)\; 2B_oL^2 Wb$ $(b) \; 3B_o L^2 Wb$ $(c) \; 4B_o L^2 Wb$ $(d) \; \sqrt{29}B_o L^2 Wb$

asked Dec 31, 2016 by priyanka.c

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