Young Modulus and Material Properties Quiz

What is the unit of the Young modulus?

• N.m-2

• N m

• N m-1

• N m2

What is the ultimate tensile stress of a material?

• the stress at which the material becomes ductile.

• the stress at which the material breaks.

• the stress at which the material deforms plastically.

• the stress at which the material reaches its elastic limit.

Which of the following correctly defines the terms stress, strain and Young modulus?

• force x area extension x original length stress ÷ strain

• force x area extension ÷ original length stress x strain

• force ÷ area extension ÷ original length stress ÷ strain

• force ÷ area extension x original length stress x strain

The tension in a spring of a natural length lo is first increased from zero to T1, causing the length to increase to l1. The tension is then reduced to T2, causing the length to decrease to l2 (as shown) Which area of the graph represents the work done by the spring during this reduction in length?

• MLP

• MNQP

• MNSR

• MPLU

A student wanted to measure the Young modulus of a wire, to do this they needed to take a number of measurements. In which row could the measurement not be made directly with the listed apparatus?

• Extension of wire Vernier scale

• Area of cross-section of wire Micrometer screw gauge

• Original length of wire Metre rule

• Mass of load applied to a wire Electronic balance

Two springs P and Q both obey Hooke's law. They have spring constant 2k and k respectively. The springs are stretched separately, by a force that is gradually increased from zero up to a certain maximum value, the same for each spring. The work done in stretching spring P is WP, and the work done in stretching spring Q is WQ. How is WP related to WQ?

• WP = ¼ WQ

• WP = ½ WQ

• WP = 2WQ

• WP = 4WQ

An experiment was carried out to determine the Young modulus of steel using a steel wire. Uncertainties in the measurements are given below. What is the percentage uncertainty in the Young modulus?

• 6.2 %

• 4.7 %

• 1.8 %

• 1.3 %

A wire is stretched by 8 mm when a load of 60N is applied. What will be the extension of a wire of the same material having four times the cross-sectional area and twice the original length, when the same load is applied?

• 2 mm

• 4 mm

• 8 mm

• 16 mm

Which of the following is the definition of the ultimate tensile stress of a material?

• The maximum inter-atomic force before the atomic bonds of the material break.

• The maximum force that can be applied to a bar of the material before it bends.

• The maximum tensile force in a wire of the material before it breaks.

• The maximum stretching force per unit cross-sectional area before the material breaks.

The table shows a load applied to four wires and the cross-sectional area of each. Which of the wires is subjected to the greatest stress?

• A 1 500 0.25

• B 2 000 1.0

• C 3 000 0.56

• D 5 000 2.3