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Class 7 Questions asked by Filo students

Views: 5,641

5.

The logic circuit shown above is equivalent to :

Topic:

Atoms, Nuclei & Dual nature

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Views: 5,438

3. A uniform thin bar of mass

6 kg

and length 2.4 meter is bent to make an equilateral hexagon. The moment of inertia about an axis passing through the centre of mass and perpendicular to the plane of hexagon is

\times 1 0^{- 1} kg m^{2}

Topic:

Mechanics

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Views: 5,799

5.If a coil of 40 turns and area

4.0 cm^{2}

is suddenly removed from a magnetic field, it is observed that a charge of

2.0 \times 1 0^{- 4} C

flows into the coil. If the resistance of the coil is

80Ω

, the magnetic flux density in

Wb / m^{2}

$0.5$
$1.0$
$1.5$
$2.0$

Topic:

Magnetism, EMI & AC

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Views: 5,856

The magnetic flux of

500 m u Wb

per turn passing through a 200 turn coil is reversed in

20 \times 1 0^{- 3}

seconds. The average e.m.f. induced in the coil in volt is

$2.5$
$5.0$
$7.5$
$10.0$

Topic:

Magnetism, EMI & AC

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Views: 5,134

A circular coil of area

8 m^{2}

and number of turns 20 is placed in a magnetic field of

2 T

with its plane perpendicular to it. It is rotated with an angular velocity of 20 rev/s about its natural axis. The emf induced is

$400 V$
$800 π V$
zero
$400 π V$

Topic:

Magnetism, EMI & AC

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Views: 5,165

Figure 15-E11 56. A

2.00 m

-long rope, having a mass of

80 g

, is fixed at one end and is tied to a light string at the other end, The tension in the string is

256 N

, (a) Find the frequencies of the fundamental and the first two overtones. (b) Find the wavelength in the fundamental and the first two overtones. 57. A heavy string is tied at one end to a movable support and to a light thread at the other end as shown in figure (15-E12). The thread goes over a fixed pulley and supports a weight to produce a tension. The lowest frequency with which the heavy string resonates is

120 Hz

. If the movable support is pushed to the right by

10 cm

so that the joint is placed on the pulley, what

Topic:

Waves & Oscillation

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Views: 5,516

Acceleration-time graph for a particle is given figure. If it starts motion at

t = 0

, distance travelle in

3 s

$4 m$
$2 m$
0
$6 m$

Topic:

Mechanics

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Views: 5,054

Number of distinct real root of the equation

l e f t ∣ x^{2} + 4 x + 3 i g h t ∣ = x + 1

2
3
4
none of these

Topic:

Mechanics

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Views: 5,563

some other units are given in Appeng your guidance and ready reference.

2.3

MEASUREMENT OF LENGTH You are already familiar with some direc for the measurement of length. For

e

Topic:

Atoms, Nuclei & Dual nature

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Question 10

Views: 5,553

Hence, option (c) represents the correct graph. 38. If a capacitor of

8 m u F

is connected to a

220 V, 100 Hz

source and the current passing through it is

65 mA

, th the rms voltage across it is:

$129.4 V$
$12.94 V$
$1.294 V$
$15 V$

Topic:

Magnetism, EMI & AC

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Question 11

Views: 5,274

cal Moment of inertia of the system about

A B

9.75

Three rods each of mass

m

and length lare joined wgether to form an equilateral triangle as shown in figure. Find whe mament of inertia of the system about an axis passing through its centre of mass and perpendicular to the plane of the triangle.

Topic:

Mechanics

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Question 12

Views: 5,845

t = 0

S

is closed. The charge on the capacitor is varying with time is

Q = Q_{0} l e f t (1 - e^{- α t} i g h t)

α

{"A) $1 0^{- 3}$ ","(1) $1 0^{9}$ ","B) $1 0^{6}$ ","D) $1 0^{3}$ "}

Topic:

Electrostats

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Question 13

Views: 6,015

51. A non-conducting disc of radius

a

and uniform positive surface charge density

σ

is placed on the ground with its axis vertical. A particle of mass

m

and positive charge

q

is dropped, along the axis of the disc from a height

H

with zero initial velocity. The particle has

q / m = 4 v a re p s i l o n_{0} g / σ

. (a) Find the value of

H

if the particle just reaches the disc. (b) Sketch the potential energy of the particle as a function of its height and find its equilibrium position.

Topic:

Electrostats

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Question 14

Views: 5,203

12. A conducting sphere of radius

r

is surrounded by a poorly conducting material of inner radius

a

and outer radius

b

whose resistivity

ρ

ρ = ρ_{0} r^{3}

. Find the resistance between the sphere and the outer surface of surrounding conducting material.

Topic:

Electrostats

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Question 15

Views: 5,490

voltage across the load lies between (2016 Adv.)

$11.7 V$ and $11.8 V$
$11.6 V$ and $11.7 V$
$11.5 V$ and $11.6 V$
$11.4 V$ and $11.5 V$

Topic:

Electrostats

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Question 16

Views: 5,882

Find the acceleration of block just after cut the string ?

$2 g - \frac{k f}{2 m}$
$8 - \frac{k ℓ}{2 m}$
$2 g - \frac{k f}{m}$
$g - \frac{k t}{m}$

Topic:

Mechanics

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Question 17

Views: 5,969

What happens if

K > 2 mg / ℓ

at equilibrium tension in string is negative
at equilibrium position change in length of spring is greater then $\frac{ℓ}{2}$
at equilibrium tension in string is zero.
If we cut the sting, block will accelerate in upword direction.

Topic:

Mechanics

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Question 18

Views: 5,286

14. The velocity of a particle moving in the positive direction of the

x

-axis varies as

v = 3 x

, all quantities being in S.L units. At time

t = 0

the particle was at

x = 0

. Then the average velocity of the particle averaged over the time the particle takes to cover

4 m

3 m / s

Topic:

Mechanics

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Question 19

Views: 5,221

12. A particle is in motion on the

x

-axis. The variation of its velocity with position is as shown. The graph is circle and its equation is

x^{2} + v^{2} = 1

x

m

v

m / s

. The CORRECT statement(s) is/are :- (A) When

x

is positive, acceleration is negative. (B) When

x

is negative, acceleration is positive.

Topic:

Mechanics

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Question 20

Views: 5,438

7.

A particle starts moving in a non-uniform circular motion, has angular acceleration as shown in figure. The angular velocity at the end of 4 radian is given by

ω rad / s

then find the value of

ω

. ISAC LEARNING

Topic:

Mechanics

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