1. What is the intensity of radiation (I)?

a. rate of heat radiation from a surface per unit area
b. rate of heat radiation from a surface per unit solid angle
c. rate of heat radiation from a surface per unit area per unit solid angle
d. none of the above

ANSWER: c. rate of heat radiation from a surface per unit area per unit solid angle

2. What is solid angle?

a. the ratio of spherical surface enclosed by a cone, with its vertex at the centre of sphere, to the radius of the sphere

b. the ratio of spherical surface enclosed by a cone, with its vertex at the centre of sphere, to the square of the radius of the sphere

c. the ratio of spherical surface enclosed by a cone, with its vertex at the centre of sphere, to the cube of the radius of the sphere

d. the ratio of spherical surface enclosed by a cone, with its vertex at the centre of sphere, to the fourth power of the radius of the sphere

ANSWER: b. the ratio of spherical surface enclosed by a cone, with its vertex at the centre of sphere, to the square of the radius of the sphere

3. What is the correct formula for the intensity of the emitted radiation of a black body (I) in terms of its emissive power (Eb)?

a. I = (Eb)
b. I = π (Eb)
c. I = 2 π (Eb)
d. I =(1/π) (Eb)