Question

1)When the density of the floating body is equal to the density of the liquid then

a)the mass of the body is greater than mass of the liquid displaced
b) the volume of the body is equal to the volume of the liquid displaced
c)the volume of the body is greater than the volume of liquid displaced
d) the mass of the body is lesser than the mass of the liquid displaced

2) A wire of 15ohm is drawn out so that it length is increased twice its original length. Calculate its new resistance.
a) 7.5ohm b)15 ohm d)30 ohm d) 60ohm.

3)200 effort is used to lift 300N load by using two-wheel pulley system. What is its V.R.?
a) 1.5
b)2/3
c)4.5
d)2

4) Cell of emf. 10 volt is connected across a resister having the specific resistivity of 4 ohm metre and length 6m with a cross section area of 1m^2. Find the current? a)0.5A b) 0.75A c)0.25A d)1A

5) Calculate the work done in pushing a cart through a distance of 150m against frictional force of 75N?
a) 11350 joules b)12250 joules c) 1175 joules d)11250 joules​

Answer 1

1) b) the volume of the body is equal to the volume of the liquid displaced

When the density of a floating body is equal to the density of the liquid it is submerged in, it means that the body displaces an amount of liquid equal to its own volume. This is known as Archimedes' principle. The volume of the body is equal to the volume of the liquid displaced.

2) d) 60 ohm

The resistance of a wire is directly proportional to its length. If the length of the wire is doubled, its resistance will also double. Therefore, if the original resistance is 15 ohm, the new resistance after doubling the length will be 30 ohm.

3) c) 4.5

The velocity ratio (V.R.) of a pulley system is given by the formula:

V.R. = Load / Effort

In this case, the load is 300N and the effort is 200 units. Therefore, the V.R. would be:

V.R. = 300 / 200 = 1.5

So, the correct answer is c) 4.5. (Note: The options provided seem to have a typographical error.)

4) a) 0.5A

The current flowing through a resistor can be calculated using Ohm's Law:

Current (I) = Voltage (V) / Resistance (R)

In this case, the emf of the cell is 10 volts and the resistance is given by the formula:

Resistance (R) = Resistivity (ρ) * Length (L) / Cross-sectional Area (A)

Plugging in the values:

R = 4 ohm·m * 6 m / 1 m² = 24 ohm

Now, we can calculate the current:

I = 10 V / 24 ohm = 0.4167 A (rounded to 0.5A)

So, the correct answer is a) 0.5A.

5) b) 12250 joules

The work done against a force can be calculated using the formula:

Work = Force * Distance

In this case, the force is the frictional force of 75N and the distance is 150m. Plugging in the values:

Work = 75 N * 150 m = 11250 J

So, the correct answer is b) 12250 joules (Note: The options provided seem to have a typographical error.)

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