1. Which of the following materials is most suitable for use as the core of an electromagnet? a
Aluminium
b
Steel
c
Soft iron
d
Copper
2. A wire carrying a current in a magnetic field may experience a force. Which of the following devices does NOT depend on this force?

a
Electric motor
b
Loudspeaker
c
Moving caoil galvanometer
d
Electromagnet
3. The rule which relates the direction of an electric current to its magnetic field is called:

a
Fleming's Left Hand Rule
b
Maxwell's Corkscrew Rule
c
Maxwell's Left Hand Rule
d
Fleming's Right Hand Rule
4. Which of the following statements is/are true?

I. Like magnetic poles attract each other

II. In magnetism, forces of attraction and repulsion are both experienced

III. The magnitude of the repulsive force between two magnetics poles increases with their separation.

a
II and III only
b
I only
c
II only
d
I and II only

answer: question1

1,000 tons

question2

3: 8

question 3

store d

step-by-step explanation:

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s

momentum of soft ball three times less than baskey ball