By using a concave mirror, image of a tree is focused on a screen. The distance between the screen and the mirror is
(a) Equal to twice the focal length of the concave mirror.
(b) Equal to one fourth of the focal length of the concave mirror.
(c) Equal to half the radius of curvature of the concave mirror.
(d) Equal to the radius of curvature of the concave mirror.
Prerna has 4 containers of the same size and thickness. They are made of different materials such as plastic, steel, styrofoam and glass. She poured the same amount of water at 90°C and placed a thermometer into each container. All the containers were placed in a room with the same conditions.
After 20 minutes, which of the following could Prerna observe?
1. All the thermometers will show the same temperature.
2. All the thermometers will show different temperature.
3. The thermometer in the steel container will show the least drop in temperature.
4. The thermometer in the styrofoam cup will show the highest temperature.
(a) 1 only
(b) 2 and 3
(c) 3 and 4
(d) 2 and 4
The diagram shows an object O viewed using two mirrors. A person looks into the mirrors as shown. At which position is the image of O seen?
pls explain me this
Ritika conducted two experiments over two soil samples and tabulated the result as shown here.
Identify the soils from results and select the correct option.
----------- P -------------------- Q
ASandy soil -------- Loamy soil
BLoamy soil -------- Sandy soil
CClayey soil -------- Loamy soil
DLoamy soil -------- Clayey soil
Figure P shows an object which is made of three different materials. Figure Q shows its shadow on a screen. Study these figures and select the option that correctly identifies any two of these materials.
A1 - Tissue paper,-----2 - Cardboard
B2 - Cardboard,--------3 - Cellophane sheet
C1 - Cardboard,--------3 - Tracing paper
D2 - Frosted glass,-----3 - Cardboard
error in the question isn't it?