$CATEGORY: Science - Khan Academy/9.Light-Reflection and Refraction/9.Light-Reflection and Refraction--Spherical Mirrors

//Multiple Choice

According to the sign convention for mirrors, the focal length of a concave mirror is\: {
    ~Positive
    =Negative
    ~Zero
    ~None of the above
}

For a convex lens, the focal length is\: {
    =Positive
    ~Negative
    ~Zero
    ~None of the above
}

In the mirror sign convention, the object distance (u) is taken as\: {
    =Positive if the object is placed to the left of the mirror
    ~Negative if the object is placed to the left of the mirror
    ~Positive if the object is placed to the right of the mirror
    ~None of the above
}

The height of an image in a concave mirror is taken as positive if the image is\: {
    ~Inverted
    =Erect
    ~Real
    ~None of the above
}

According to the sign conventions for lenses, an object placed on the left side of the lens has\: {
    ~Positive object distance
    =Negative object distance
    ~Zero object distance
    ~None of the above
}

The focal length of a convex mirror is\: {
    ~Always positive
    =Always negative
    ~Zero
    ~None of the above
}

The power of a convex lens is always\: {
    =Positive
    ~Negative
    ~Zero
    ~None of the above
}

//True or False

The focal length of a concave mirror is positive. {F}

The focal length of a convex lens is always positive. {T}

The object distance is taken as negative if the object is placed to the left of the lens. {T}

The height of the image is positive if the image is inverted. {F}

The focal length of a concave lens is positive. {F}

For a concave mirror, the image distance is negative if the image is real. {F}

The height of the object is always taken as positive, regardless of the orientation of the image. {T}

The focal length of a convex mirror is negative. {T}

The power of a concave lens is positive. {F}

In a convex lens, the object distance is taken as negative if the object is placed to the left of the lens. {T}


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