In a stack there are 5 books each of thickmen 20mm and 5 paper sheets each of thickmen 0.016 mm.What is the total thickmen of the stack?

A student measures the thickness of a human hair by looking at it through a microscope of magnification 100. He makes 20 observations and finds that the average width of the hair in the field of view of the microscope is 3.5 mm. What is the estimate on the thickness of hair ?

Two strips of metal are riveted together at their ends by four rivets, each of diameter 6.0 mm. What is the maximum tension that can be exerted by the riveted strip if the shearing stress on the rivet is not to exceed 6.9xx10^(7) Pa ?

In a Young’s double slit experiment, the distance of screen from slits is 2 m. The fringe width is 0.5 mm. If a thin glass plate of thickness 0.05 mm and n = 1.5 is placed over one of the slits, then the lateral displacement of fringes will be (lambda= 6000 overset@A)

The lamp of flash light is 1.5 Omega . It uses 3 cells each of 1.5 V and internal resistance 0.25 Omega . What is the net potential difference across the lamp ?

A spiral is made up of successive semicircles, with centres alternately at A and B, starting with centre at A, of radii 0.5 cm , 1.0 cm, 1.5 cm, 2.0 cm,… as shown in Fig. 54. What is the total length of such a spiral made up to thirteen consecutive semicircles ? (Take pi = (22)/(7) )

In a biprism experiment the distance of the second maximum was 2.0 mm on a screen 1 m away from 0.5 mm apart slits. What is the wave length of light ?

The cylindrical tube of a spray pump has a cross section of 8.0 cm^2 one end of which has 40 fine holes each of diameter 1.0 mm. If the liquid flow inside the tube is 1.5 m min^-1 . What is the speed of ejection of the liquid through the holes?

You are given marbles of diameter 10mm . They are to be placed such that their centres are laying in a square bound by four lines each of length 40mm . What will be the arrangements of marbles in a plane so that maximum number of marbles can be placed inside the area? Sketch the diagram and derive expression for the number of molecules per unit area.

A circular coil of 20 turns and radius 10 cm is placed in a uniform magnetic field of 0.10 T normal to the plane of the coil. If the current in the coil is 5.0 A, what is the (a) total torque on the coil, (b) total force on the coil, (c) average force on each electron in the coil due to the magnetic field? (The coil is made of copper wire of cross-sectional area 10^(-5) m^2 , and the free electron density in copper is given to be about 10^29 m^(-3) .)