A12-inch object is placed 30 inches in front of a plane mirror. a ray of light from the object strikes the mirror at a 45-degree angle.

how tall is the image produced by the mirror?

12 inches

30 inches

24 inches

45 inches

Answer : The correct option is (A) "12 inches"

Explanation :

It is given that, a 12-inch object is placed 30 inches in front of a plane mirror. A ray of light from the object strikes the mirror at a 45-degree angle ( from fig) .

In case of plane mirror, the size of image is exactly same as that of size of object.

So, we can say that the size of image produced by the plane mirror is 12 inches.

Hence, the correct option is (A) i.e. 12 inches.

  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

the total distance traveled by the car is

30km + 49km = 79 km .