Sec 4 Challenge 3

A man has three sons.

What is the chance of his next child being a daughter?

• 0%

• 25%

• 50%

• 100%

Hydrocarbons obtained by fractional distillation of petroleum can be cracked to make useful products. Which substance could not be obtained by cracking propane, Mr₄₄?

• C₂H₄

• C₂H₄

• C₂H₄

• C₂H₄

Which diagram represents the voltage output of a simple a.c. generator?

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• 
• 
• 

The diagram shows a reflex arc.

Which label identifies the motor neuron?

• A

• B

• C

• D

The element vanadium, V, forms several oxides. In which change is oxidation taking place?

• 
• 
• 
• 

The graph shows how the decay rate of a radioactive source changes with time.

What will be the decay rate at 8 days?

• 0 decays / s

• 125 decays / s

• 250 decays / s

• 500 decays / s

What is the role of insulin?

• It decreases blood glucose concentration.

• It increases blood glucose concentration.

• It decreases blood sucrose concentration.

• It increases blood glycogen concentration.

A hole is made in a square tile of uniform thickness. The diagram shows the tile hanging loosely on a nail. Where is the centre of gravity of the tile?

• A

• B

• C

• D

A salt is produced in each of the following reactions.

• 1, 2 and 3

• 1 and 2 only

• 1 and 3 only

• 2 and 3 only

A plastic rod is rubbed with a cloth. The rod becomes positively charged. What happens to the plastic rod and what is the charge on the cloth?

• A

• B

• C

• D